Seminars and Colloquia at ESO Garching and on the campus

December 2012

20/12/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Galaxy Clusters: tools for cosmology and laboratories for astrophysics
Stefano Borgani (INAF - Trieste Observatory)
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Abstract

In my talk I will first briefly review the application of galaxy clusters as tools to trace cosmic evolution. I will then discuss the recent advances in the this field, as driven by the increasing quality of observational data, and by the much improved description of clusters through detailed numerical simulations. In this context I will present recent results on the analysis of such simulations aimed at calibrating clusters as precision tools for cosmology. Finally, I will highlight the potential that future large surveys of galaxy clusters could have to trace the growth of cosmic structures and to shed light on the constituents of the Universe and the nature of primordial perturbations.

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18/12/12 (Tuesday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Shadows, gaps, and ring-like structures in proto-planetary disks
Ralf Siebenmorgen (ESO Garching)

Abstract

We study the structure of passively heated disks around T Tauri and Herbig Ae stars (AA 539, 2012) and present a vectorized Monte Carlo dust radiative transfer model (ApJ 751, 2012). The vectorization provides a speed up factor of 100 when compared to a scalar version of the code. Proto-planetary disks are composed of either fluffy carbon and silicate grains of various sizes or dust of the diffuse ISM. The IR emission and the midplane temperature derived by the MC method differ from models where the radiative transfer is solved in slab geometry of small ring segments. Under the assumption of hydrostatic equilibrium we find that the disk in the inner rim puffs up, followed by a shadowed region. The shadow reduces the temperature of the midplane and decreases the height of the extinction layer of the disk. It can be seen as a gap in the disk unless the surface is again exposed to direct stellar radiation. There the disk puffs up a second time, a third time and so forth. Therefore several gaps and ring-like structures are present in the disk surface and appear in emission images. They result from shadows in the disks and are present without the need to postulate the existence of any companion or planet. As compared to Herbig Ae stars, such gaps and ring--like structures are more pronounced in regions of terrestrial planets around T Tauri stars. We present an accurate treatment of PAH molecules in the MC code. Particular attention is given to the photo-dissociation of the molecules by energetic photons. We consider beside PAH destruction also the survival of the molecules by vertical mixing within the disk (see Fig.). By applying typical X-ray luminosities the model accounts for the low PAH detection probability observed in T Tauri and the high PAH detection statistics found in Herbig Ae disks (AA 543, 2012). Spherical halos above the disks and mid--IR images are presented. We show that disks are easier to resolve when PAH emission dominates.
14/12/12 (Friday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Lunch Talk
Talk — The physics of massive-star magnetism explored through the MiMeS and BinaMIcS large projects
Gregg Wade (Royal Military College of Canada)

Abstract

Since 2008, the Magnetism in Massive Stars (MiMeS) large programs at ESO, TBL and CFHT have led to a transformation of our understanding of the phenomenon of magnetism in hot OB stars. Starting in 2013, the new Binarity, Magnetism and Interactions in Stars (BinaMIcS) project will bring a fundamental new ingredient to these investigations: the influence and importance of close binarity on massive-star magnetism, and the unique interactions that result thereby. In this presentation I will review the results of the MiMeS survey, discussing in particular the properties of newly-discovered magnetic O-type stars, and introduce the scope and objectives of the BinaMIcS project.
13/12/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Formation and Evolution of Accreting Binaries: Insight from Multiwavelength Observations of Galaxies Both Near and Far!
Bret Lehmer

Abstract

X-ray emission from accreting binary systems (X-ray binaries) provides a unique signature of the binary phase of stellar evolution and compact object populations (neutron stars and black holes). Through detailed X-ray and multiwavelength observations (e.g., from Chandra, Hubble, Spitzer, and other telescopes) of both nearby and distant galaxies, I am working on obtaining a more complete picture of how stars and compact objects formed and evolved throughout the history of the Universe. I will present ongoing and planned observational efforts to characterize (1) how the formation of X-ray binary populations in nearby galaxies is linked to the physical properties of the galaxies themselves (e.g., galaxy morphology, star-formation activity, stellar mass, stellar age, and metallicity); and (2) how X-ray binary populations evolved over the last 12 billion years of cosmic history (since z ~ 4) in response to significant changes in the physical properties of their host galaxies. I will highlight how forthcoming and archival observations, future multiwavelength telescopes, and binary population synthesis modeling will provide a powerful blend of resources for improving our understanding of X-ray binaries and compact objects.
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy for Non-Astronomers
Talk — Death from Space
Gero Rupprecht (ESO Garching)

Abstract

The World will end on December 21, 2012. At least that’s what some people proclaim. But is it true? One thing is sure: Somewhere out there in the solar system a killer asteroid is heading for a deadly collision with our Blue Planet. Unfortunately we don’t know, which of the millions of asteroids it is and when it might strike… Interestingly the Universe has more in store for us than mere asteroids, dangers worth of a good night’s nightmare!
06/12/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — What spectral Fingerprints of Exoplanets reveal
Lisa Kaltenegger (MPI f. Astronomie, Heidelberg)
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Abstract

A decade of exoplanet search has led to surprising discoveries, from giant planets close to their star, to planets orbiting two stars, all the way to the first extremely hot, rocky worlds with potentially permanent lava on their surfaces due to the star's proximity. Observing mass and radius alone can not break the degeneracy of a planet's nature due to the effect of an extended atmosphere that can also block the stellar light and increase the observed planetary radius significantly. Even if a unique solution would exist, planets with similar density, like Earth and Venus, present very different planetary environments in terms of habitable conditions. Therefore the question refocuses on atmospheric features to characterize a planetary environment and what the spectra of an exoplanet can reveal.

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10:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Astronomical Site Testing in the Canadian High Arctic
Paul Hickson

Abstract

The Earth's polar regions offer cold, dry, stable atmospheric conditions and long periods of continuous darkness. Extensive testing of sites on the Antarctic plateau has revealed that, above a strong surface layer, the seeing is exceptional. But, the remoteness and icy expanse of Antarctica presents great practical challenges. The Arctic, in comparison, is more easily accessible and offers mountainous terrain well-suited for astronomical telescopes. This has motivated a small team to begin exploring several possible astronomical sites in the Canadian Arctic Archipelago. I will give an overview of this program and its principal findings to date, and discuss surprising results from measurements of optical turbulence and seeing in the lower Arctic atmosphere.
04/12/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Evolution in galaxy cluster cores since z=1
Claire Burke (Liverpool John Moores University)

Abstract

The central regions of galaxy clusters are usually dominated by a massive brightest cluster galaxy (BCG), which generally sits at the centre of mass of the cluster, and a diffuse halo of intracluster light which can be extend beyond the cluster limits. BCGs are the most massive, most luminous galaxies observed in the Universe and their unique positions at cluster centres make them ideal for studying the buildup of large scale structures. A significant fraction of the total baryonic mass and luminosity of galaxy clusters is thought to be contained within the intracluster light (ICL), and the study of the ICL can reveal details of the evolution histories and processes occurring within galaxy clusters. I will review the current theory on the formation and evolution of these most massive galaxies and present the results of our recent observational studies on the evolution of BCGs and the ICL between half way back to the big bang and the present. Our studies show that BCGs are almost fully assembled half way back to the big bang and show almost no evolution up to the present day, in stark contrast to the predictions of cosmological simulations which state that BCGs should double in mass over the this time. The ICL, however, shows substantial growth and evolution over this time. These results point to a rapid early assembly of massive galaxies in clusters followed by passive evolution, with interactions between galaxies in clusters mainly occurring by stripping to build up the ICL at later times.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — The young stellar population of the Carina Nebula
Henrike Ohlendorf (LMU)

Abstract

Containing several thousands of young stars, the Carina Nebula region is a prime target for large-scale studies of young stars. With infrared data taken with Spitzer, Herschel, WISE and VISTA, we are able to study its young stellar population, both individually and on a large scale. What kinds of stars are there to be found? How are they distributed? Are they triggering each other? What kinds of features do they exhibit? In my talk I will summarise our ongoing infrared study of the Carina Nebula region and the inferences for the young stellar population that can be drawn from it.
09:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Workshop — Real Time Control for Adaptive Optics

November 2012

29/11/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The universal dark matter density profile and its destruction
Andrew Pontzen (Oxford University)
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Abstract

I review some recent developments in attempting to reconcile the observed galaxy population with numerical models of structure formation in the 'LCDM' concordance cosmology. Focussing on behaviour of dwarf galaxies, I describe the infamous 'cusp-core' dichotomy - a long-standing challenge to the LCDM picture on small scales - and use toy models to show how it is resolved in recent numerical simulations (Pontzen & Governato 2012). I then discuss the current observational status of this picture (Teyssier, Pontzen & Read 2012; Penarrubia et al 2012). In the second half of the talk, I apply the analytic techniques developed for probing the effect of gas on dark matter dynamics to the question of how, in the absence of baryons, a universal "NFW" dark matter halo profile emerges (independent of scale or details of the initial conditions). Thus the generation of NFW halos on the one hand and the destruction of their central cusps on the other can be ascribed to surprisingly similar physical arguments.

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28/11/12 (Wednesday)
09:30, Fornax (ESO HQ, Garching) | ESO Garching
Workshop — Islands in the Cosmos: multi-wavelength views of galaxy formation and evolution
27/11/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Cosmic chronometers: a new approach to constrain the expansion history of the Universe
Michele Moresco (University of Bologna)

Abstract

The determination of the expansion history of the Universe is one of the most crucial measurements for cosmology, since the rate at which it decelerates/accelerates directly depends on the energy components which characterize it (and, in particular, the "dark energy", in case of an accelerated expansion). It is therefore fundamental to measure it, i.e. the Hubble parameter H(z), very precisely. In this talk I will present an innovative method to obtain direct constraints on H(z) from the differential age evolution of cosmic chronometers. I will provide the basic theoretical background of this approach, and I will as well discuss its dependence on assumptions and systematics. The "cosmic chronometers" approach has been recently used to obtain new high-accuracy measurements of H(z) up to z~1.1 from the analysis of a large sample of massive and passive ETGs. I will present these results, focusing the attention in particular to their cosmological consequences, showing the potentiality of this technique to discriminate amongst different cosmologies. I will also demonstrate that this approach can be not only complementary, but also competitive with the other "standard" probes, i.e. SNe and BAO.
22/11/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Galaxy Nuclei, Galaxy Outskirts
Jenny Greene (Princeton)
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Abstract

I will talk about two different aspects of massive galaxy evolution. First, I will discuss the assembly of elliptical galaxies based on high signal to noise spectra beyond the effective radius taken with an integral-field spectrograph. The stars in the outskirts of these galaxies are enriched in alpha elements but have low metallicity, similar to thick disk stars in our galaxy. We suggest that these stars were accreted from small galaxies that formed early and had a truncated star formation history. Second, I will discuss supermassive black hole scaling relations, and what they may tell us about the coevolution of black holes and galaxies. I will end with tantalizing new clues about the lifetimes of sub-pc supermassive black hole binaries.

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11:00, D29 | ESO Garching
Talk — Fundamentals of mm interferometry: Imaging
Robert Laing (ESO)

Abstract

Imaging: gridding, weighting, deconvolution methods, self-calibration, primary beams and direction-dependent effects. Effects of missing data. Mosaics. Combining arrays/single-dish data.
20/11/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — The role of the structure formation process in regulating the galaxy star formation activity
Paola Popesso (MPE)

Abstract

Achieving an observational determination and a theoretical understanding of the Cosmic Star Formation History (CSFH) of the Universe is one of the biggest challenges in the study of galaxy formation and evolution. The most striking feature of the CSFH is a dramatic drop of the star formation rate, since z~1 to the present day, after a rather constant phase of high activity at z~1-2 or above. A quenching process is required to trigger such an abrupt decrease of the Star Formation (SF) activity. As a matter of fact, the progressive decline of the SF activity of the Universe since z~1 anti-correlates with the late-time increase of the number density of group-sized halos. It is, then, mandatory to follow this tantalizing lead and to ask if the very same process of assembly and growth of structures may be the main cause, or one of the major drivers, of the 1 order of magnitude decline in the CSFH. I will tackle this issue by showing that group galaxies evolve much faster than galaxies in low density regions. Star forming group galaxies, in particular, are perfectly on the Main Sequence (MS) at z~1 whereas at lower redshift they are quenched, thus, dropping off the MS quicker than field galaxies towards the region of SF quiescence. I will also show that the efficiency of the quenching process depends on the halo mass, being more efficient in the most massive halos, and thus, in most massive galaxies that tend to reside in such halos.
19/11/12 (Monday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Time-domain observations of young stars
Aleks Scholz (Dublin Institute for Advanced Studies)

Abstract

Variability in fluxes, colours, and emission lines is a key feature of young stellar objects and is found at all stellar masses from Herbig Ae/Be stars down to brown dwarfs. The study of YSO variability was and still is one of the major drivers for the development of our understanding of star and planet formation. In this talk I will discuss our ongoing projects to characterise YSOs in the time domain and to use variability to constrain stellar rotation, magnetic activity, accretion, and disk properties. In particular, I will present new results from the project LAMP (Long-term Accretion Monitoring Program) and from a systematic survey for extreme variables, including the discovery of two new potential FU Ori-type objects. I will argue that we are witnessing a renaissance of this field, triggered by new resources that will allow us for the first time to study YSO variability in a comprehensive way.
09:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Workshop — Short course on optical alignment and testing
16/11/12 (Friday)
12:30, D29 | ESO Garching
Instrument Lunch Talk
Talk — CRIRES
Ulli Kaeufl, Michael Hilker (ESO)
15/11/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — A deep look into AGN: accretion and outflow of gas in Mrk 509
Jelle Kaastra (SRON Utrecht)
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Abstract

A major uncertainty in models for photoionised outflows in AGN is the distance of the gas to the central black hole. We present the results of a massive multiwavelength monitoring campaign on the bright Seyfert 1 galaxy Mrk 509 to constrain the location of the outflow components dominating the soft X-ray band. Mrk 509 was monitored by XMM-Newton, Integral, Chandra, HST/COS and Swift in 2009. We have studied the response of the photoionised gas to the changes in the ionising flux produced by the central regions. We were able to put tight constraints on the variability of the absorbers from day to year time scales. This allowed us to develop a model for the time-dependent photoionisation in this source. We find that the more highly ionised gas producing most X-ray line opacity is at least 5 pc away from the core; upper limits to the distance of various absorbing components range between 20 pc up to a few kpc. The more lowly ionised gas producing most UV line opacity is at least 100 pc away from the nucleus. These results point to an origin of the dominant, slow (v < 1000 km/s) outflow components in the NLR or torus-region of Mrk 509. We find that while the kinetic luminosity of the outflow is small, the mass carried away is likely larger than the 0.5 Solar mass per year accreting onto the black hole. We also determined the chemical composition of the outflow as well as valuable constraints on the different emission regions. We find for instance that the resolved component of the Fe-K line originates from a region 40-1000 gravitational radii from the black hole, and that the soft excess is produced by Comptonisation in a warm (0.2-1 keV), optically thick (tau~10-20) corona near the inner part of the disk.

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12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy for Non-Astronomers
Talk — Hubble in Orbit - Two Decades and Counting
Bob Fosbury (Astronomer Emeritus)

Abstract

During May 2009, the Hubble Space Telescope was subject to the most intense overhaul of its life with astronauts from the Space Shuttle Atlantis performing engineering feats far beyond what was originally envisaged for orbital servicing. Instruments were repaired and replaced during the most complex human process that had yet been performed in space. The telescope is now some hundred times more powerful than when it was launched in 1990. This is the story of Hubble, looking back on the revolution in astrophysics that it has achieved and forward to what it is achieving now in its probings of the early history of the universe to the study of the atmospheres of extrasolar planets.
14/11/12 (Wednesday)
16:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — The Emerald Planet: How plants changed Earth’s atmosphere
David Beerling (Sheffield University, UK)
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Abstract

The colonization of the continents by land plants over 450 million years was one of the most far-reaching chapters in the history of life on Earth. It fundamentally changed the ecology and climate of the planet. In this talk, I will discuss how new findings are supporting the exciting long-standing hypothesis that symbiotic relationships between early land plants and soil-dwelling fungi fuelled the ‘greening of the Earth’, and how by relentlessly burning fossil photosynthesis we are threatening to destabilize the climate system with potentially disastrous impacts for future generations and nature. Given that astronomers will eventually be able to diagnose the composition and state of the atmospheres of planets in the 'habitable zone', I will outline some of the atmospheric changes that might be expected to relate to plant evolution.

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09/11/12 (Friday)
12:30, D29 | ESO Garching
Instrument Lunch Talk
Talk — FORS1/2
Mario van den Ancker, Gero Rupprecht (ESO)
08/11/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Event Horizon Telescope: Observing Black Holes with Schwarzschild Radius Resolution
Shep Doeleman
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Abstract

It is now almost certain that at the center of our Milky Way Galaxy lies a super massive black hole - 4 million times more massive than our Sun. Because of its proximity to Earth, this object, known as Sagittarius A*, presents astronomers with the best opportunity in the Universe to spatially resolve and image a black hole Event Horizon. To do this requires using Very Long Baseline Interferometry (VLBI), the technique whereby radio telescopes around the world are linked together in a Global phased array. Very short wavelength VLBI observations have now confirmed structure on ~4 Schwarzschild radius scales within SgrA*, and have revealed time variability in this source on the same spatial scales. For the much more massive (6 billion solar mass) black hole powering the relativistic jet in M87, similarly compact structures have been detected. I will describe the instrumentation efforts that enable these observations, discuss what current and future VLBI observations can tell us about these super-massive black holes, and describe plans for assembling a Global submm-VLBI Event Horizon Telescope.

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06/11/12 (Tuesday)
13:00, D29 | ESO Garching
Lunch Talk
Talk — The CO connection to the radio-FIR correlation in M51
Gaelle Dumas (IRAM, France)

Abstract

I will present first results of the PdBI Arcsecond Whirlpool Survey (PAWS, PI E. Schinnerer). PAWS has imaged the CO(1-0) emission in the central 8 kpc of the nearby galaxy M51. Our final data is a combination of the IRAM 30m single-dish and PdBI observations. It reaches a resolution of about 40pc and is sensitive to Giant Molecular Clouds (GMCs) above 10^5 Msun. This data allow us to study in great details the properties of the GMCs in this galaxy and in particular we investigate the relations of the molecular gas to other tracers of the ISM. In this talk I will present a study of the relation between the CO emission, the radio continuum and the IR emission as a function of galactic environment. I'll discuss these results in the context of cosmic ray electrons diffusion and its relation to the star formation processes.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Dust evolution during the star-planet formation process
Leonardo Testi (ESO)

Abstract

I will discuss what we think we know of the evolution of solids in protoplanetary disks towards the formation of planetesimals. I will try to focus on which are the main questions that we still need to address to understand the evolution of solids in disks. As we figured out that significant grain growth seem to be occurring at earlier stages of evolution of the forming star, I will also try to expand the picture to discuss how we can try and probe the evolution of grains from the molecular cloud, to the core and protostellar stages of star formation.

October 2012

31/10/12 (Wednesday)
09:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Liquid Mirror Telescopes
Paul Hickson (Univ. of British Columbia, Canada)

Abstract

More than 150 years ago Ernesto Capocci proposed the idea of a telescope employing a rotating liquid to form a parabolic mirror. The technological challenges to this concept were overcome only in the past two decades. Liquid-mirror telescopes having apertures as large as 6-meters have now been built and used for space surveillance, adaptive optics development, and atmospheric research. A 4-meter astronomical liquid-mirror observatory is expected to begin operations next year, at a site in the Himalayan mountains of Northern India. The talk will chronicle the development of this new technology, discuss the concepts and the applications, and explore the possibilities for future large-aperture liquid-mirror telescopes on the Earth and Moon. About the speaker: Paul Hickson is Professor at the University of British Columbia (Canada), Department of Physics and Astronomy. His research interests include galaxies, galaxy groups, astronomical instrumentation and adaptive optics. He is best known for his Catalog of Compact Groups of Galaxies (1984), but has also worked to develop liquid mirror telescopes, including the NASA 3m and the UBC 6m Large Zenith Telescope, and on the development and application of lunar scintillometers for optical turbulence measurements in the arctic and other observing sites. He has served on various committees, including a term as President of the Canadian Astronomical Society (2006-2008). Presently he is Co-chair of the Science Advisory Committee for the TMT project and Project Scientist for the TMT/NFIRAOS AO system. Prof. P. Hickson is on a three month sabbatical leave at ESO/TEC until December 15th 2012.
30/10/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Star formation in nearby young clusters
Catarina Alves de Oliveira (Herschel Science Centre (ESA))

Abstract

The rapid advances in infrared detector technology over the past decades have impelled the development of wide-field instruments, and shaped our view of the cold universe. Large infrared and submillimeter surveys of nearby star-forming regions in our Galaxy can pierce the obscuring dust to reveal embedded young stars and protoplanetary disks, and also uncover the cold large-scale structure of molecular clouds. I will present results from two projects based on such datasets, namely, i) to constrain the formation scenarios of substellar objects, and ii) study the connection between filamentary structure and star formation activity. In the first project, we make use of a deep WIRCam/CFHT imaging survey of two young clusters (Rho Oph and IC348) to uncover candidate substellar members. Through an extensive spectroscopic follow-up (using SofI/NTT, NICS/TNG, ISAAC/VLT, Osiris/GTC, and GNIRS/Gemini) we derive a reliable census of their substellar population down to a few Jupiter masses, which is used to study the initial mass function, mass segregation, and the properties of brown dwarf disks using new PACS/Herschel observations. In the second project, we use Herschel observations of the Chamaeleon molecular cloud complex, which contains three dark clouds with a dramatically different star formation activity, to investigate the connection between the properties of its filamentary structure and the on-set of star formation.
26/10/12 (Friday)
14:00, D29 | ESO Garching
Talk — Fundamentals of mm interferometry: Calibration
Robert Laing (ESO)

Abstract

Calibration: atmospheric effects, complex gain, amplitude, phase and delay, bandpass, measurement equation and polarization.
12:30, D29 | ESO Garching
Lunch Talk
Talk — The interplay between molecular and ionized gas surrounding massive embedded stars
Katharine Johnston (MPIA Heidelberg)

Abstract

Although there is much evidence that B-stars (~3-15 Msun) form similarly to their low-mass counterparts, the picture is not so clear for O-stars. In this talk I present studies of two highly luminous (>10^5 Lsun) embedded O-star precursors, AFGL2591 and AFGL4176. Our aims were to determine whether the properties of these forming stars, such as the circumstellar structure, outflow and jet could be described satisfactorily by the properties of low-mass protostars, and to understand how the formation of an HII region may interrupt accretion or outflow onto/from the forming star. To this end, we used a variety of cm and mm interferometric observations to trace both the molecular and ionized gas. In addition, I will present our current results from radiative transfer modelling of these two sources, which provide insight into the density and velocity structure of their circumstellar material.
25/10/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Clearing of Discs around Young Stars
Cathie Clarke (IoA Cambridge)
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Abstract

Circumstellar discs in young stars provide the raw material - gas and dust - for planet formation; discs also effect the radial re-distribution of planets and thus play a major role in shaping planetary architecture. Understanding the interplay between discs and planet formation and migration therefore requires a good understanding of how discs evolve and how they are dispersed. Currently, however, it is still debated whether discs are self-consumed through planet formation or whether planet formation occurs in competition with some other agent for disc dispersal. Much of this talk is devoted to new work that shows how the photoevaporation of gas from such discs by Xrays from the central star is an important agent for disc dispersal. The talk gives an overview of the disc properties that can be deduced from multi-wavelength data, increasingly supplemented by imaging, showing that our now good statistical knowledge of various stages of disc clearing is largely thanks to large scale surveys conducted in recent years by the Spitzer Space Telescope. I will briefly discuss the several candidate disc clearance mechanisms and then describe the theory of Xray photoevaporation in more detail, including also some observational signatures and possible discriminants. I conclude with a description of the bewildering zoo of "transition discs" (i.e. discs with cleared inner regions) and discuss the extent to which they can be understood in terms of clearing by photoevaporation / planet formation.

Video

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23/10/12 (Tuesday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — CALYPSO: A dive into the small-scale physics and chemistry of young envelopes, disks and outflows
Anaelle Maury (ESO)

Abstract

Despite some progress in the past two decades, the physics of the youngest protostars (Class 0 objects) remains poorly understood. The mere existence of accretion disks and protobinaries at the Class 0 stage is highly controversial. Likewise, the launching mechanism of protostellar jets and their net contribution to mass and angular momentum extraction during protostar formation is strongly debated. The complex velocity and density structure shaping the inner protostellar environment is also a great puzzle to star formation models. Solving these issues, which all have a strong bearing on the long-standing "angular momentum problem" of star formation, is of paramount importance. To this aim, we obtained a comprehensive, systematic study of the nearest low-luminosity Class 0 objects with the A & C arrays of PdBI, also supported by a parallel MHD simulation effort. The CaLYPSO (Continuum and Line Young ProtoStellar Object) survey, carried out with both the IRAM 30-m telescope and Plateau de Bure Interferometer, targets 17 nearby Class 0 protostars in 3 different spectral setups, at subarcsecond resolutions reaching ~50AU scales. It is the most complete high-resolution survey of Class 0 objects carried out so far. I will present our first completed set of observations, and I will discuss the complementarity of continuum observations and line tracers to draw a comprehensive picture of the small scale infall/accretion processes in Class 0 envelopes. I will also show how our observations allow us to put unprecedented constraints on inner (50-500 AU) envelope properties and chemistry, as well as the disk formation scenario.
18/10/12 (Thursday)
16:15, *** EXCEPTIONALLY IN THE MPE NEW SEMINAR ROOM, 1.1.18b *** | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Stellar Archaeology: New Science with Old stars
Anna Frebel (M.I.T.)

Abstract

The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars are relics from the high-redshift Universe, they probe the chemical and dynamical conditions as the Milky Way began to form, the origin and evolution of the elements, and the physics of nucleosynthesis. They also provide constraints on the nature of the first stars, their associated supernovae and initial mass function, and early star and galaxy formation. I will discuss examples of the most metal-poor Galactic stars with extreme and unusual abundance patterns that can help elucidate the supernovae responsible for their chemical signatures. Furthermore, stars displaying a strong overabundance of the heaviest elements, in particular uranium and thorium, can be radioactively dated, giving formation times ~13 Gyr ago, similar to the ~13.7 Gyr age of the Universe. I then transition to a description of recent discoveries of extremely metal-poor stars in dwarf satellites of the Milky Way. Their stellar chemical signatures support the concept that small systems analogous to the surviving dwarf galaxies were the building blocks of the Milky Way's low-metallicity halo. This opens a new window for studying galaxy formation through stellar chemistry.
15/10/12 (Monday)
09:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Workshop — Science from the Next Generation Imaging and Spectroscopic Surveys
12/10/12 (Friday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Lunch Talk
Talk — Title: Kinematic structure and metallicity distribution of the Carina dSph galaxy
Michele Fabrizio (University of Rome "Tor Vergata")

Abstract

Dwarf galaxies are the crossroad of significant theoretical and observational efforts, but we still lack firm constraints concerning their formation and evolution. They are also fundamental laboratories to investigate the impact of the environment on chemical evolution in stellar systems with total masses between giant galaxies and globular clusters. We present accurate iron abundance measurements for 44 red giants (RGs) in the Carina dwarf spheroidal galaxy using high-resolution spectra (R~38,000) collected with UVES at ESO/VLT. For the 27 stars for which we measured both [FeI/H] and [FeII/H] abundances, we found evidence of NLTE effects between neutral and singly-ionized iron abundances. We also present recent results concerning the kinematics properties of the Carina dwarf spheroidal. We performed precise radial velocity (RV) measurements of two thousands of stars covering the entire body of the galaxy. The individual spectra (21,340) were collected using FORS2 (low-), GIRAFFE (medium- and high-) and UVES (high-resolution) at the VLT. The RV distribution of the ~1,370 candidate Carina stars indicates the occurrence of secondary features across the galactic center. These findings are reminiscent of a substructure with transition properties, already detected in dwarf ellipticals, and call for confirmation by independent investigations.
11/10/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Multiple populations in globular clusters
Raffaele Gratton (INAF - Padua Observatory)
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Abstract

Recent spectroscopic and photometric observations have revealed that massive stellar clusters are not made of a single stellar population but rather host multiple populations. Also, they should have been produced within very extensive episodes of star formation, which involved much more stars than currently present in the globular clusters. I will review the evidences for multiple populations in globular clusters and explore some of its implications on their formation and early history. I will also comment on the relation between the formation of the globular clusters and that of the galactic halo, and implicitly of all stellar populations characterized by a high relative frequency of globular clusters.

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09/10/12 (Tuesday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Lunch Talk
Talk — The SMC in space and time: star formation history of a prototype dwarf irregular galaxy
Monica Tosi (INAF - Astron. Obs. Bologna)

Abstract

The SMC is an excellent benchmark for galaxy evolution studies, both as the closest representative of galaxies of the most diffuse morphological type, dwarf irregulars, and as member of the closest triple galaxy system. I will present our recent studies of the SFH of several regions of the SMC. These results are currently based on HST photometry, to be soon complemented with a complete and deep photometric coverage of the galaxy performed with VST-GTO. They are part of a multi-fold project aimed at deriving information on the evolution of the SMC and of dwarf galaxies in general.
04/10/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Quasars Probing Quasars: Circumgalactic Gas in Absorption and Emission
Joe Hennawi (MPIA Heidelberg)
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Abstract

I will argue that observations of the diffuse gas in the outskirts of galaxies, the so called circumgalactic medium, are essential for constraining the 'initial conditions' for galaxy formation. Such observations provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than molecule or star-formation. A novel technique will be introduced, whereby a foreground quasar (and massive galaxy) can be studied in absorption against a background quasar, resolving scales as small as 30kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around massive proto-galaxies. I will summarize the implications of these new measurements in the context of galaxy formation models, and also discuss a sensitive search for emission from the same gas we study in absorption.

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02/10/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Deep 21-cm HI Observations with the Arecibo Telescope
Laura Hoppmann (ICRAR and Univ. of Western Australia)

Abstract

The star formation rate (SFR) in galaxies, as measured by optical, UV and far-infrared observations, appears to increase by an order of magnitude over the redshift interval of z=0 to z≈1. However, little accurate information about the co-evolution of neutral hydrogen is available. Measurements are limited to sparse and model-dependent observations of damped Lyman-α systems at high redshifts or to observations of 21cm radio emission line at very low redshift. However, the unique sensitivity of the Arecibo telescope can be used to directly detect 21-cm HI emissions from galaxies at cosmological distances. Previous detections have involved optically pre-selected galaxies and are therefore biased in their selection criteria. Here we present results from the ongoing Arecibo Ultra Deep Survey (AUDS) which is a blind 21-cm survey with the Arecibo L-band Feed Array (ALFA). We use data from AUDS to accurately derive the HI mass function and constrain the cosmic HI density ΩHI at redshifts greater than zero for the first time.

September 2012

27/09/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — From the IMF to the S-Process in Early-Type Galaxies
Charlie Conroy (UCO / Lick Observatory)

Abstract

Our understanding of the stellar populations of unresolved galaxies is fundamentally limited by our lack of knowledge of the stellar initial mass function (IMF), and its variation with environment and epoch. In this talk I will present a technique that provides direct measurements of the low-mass IMF (~0.1-1 Msun) in unresolved stellar systems. When this technique is applied to high-quality optical-NIR spectra of nearby early-type galaxies, evidence is found for an IMF that is substantially more "bottom-heavy" than the Galactic IMF. I will also discuss ongoing work aimed at measuring elemental abundances (including C, N, O, Na, Mg, Ca, Ti, Cr, Mn, Fe, Sr, and Ba) of these galaxies, with the goal of constraining their formation histories.
25/09/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — A History of Photosynthesis Research, 1840-1960
Kärin Nickelsen (LMU Munich)

Abstract

Photosynthesis is known as the process by which green plants utilize the energy of sunlight to produce carbohydrates from carbon dioxide and water in the green parts of the plant. It is fundamental to life on earth, and the way organisms accomplish this task has intrigued scientists for centuries. The first tentative (and rather simplistic) ideas were developed by organic chemists around 1840, while by 1960 an elaborate photosynthesis model at a molecular level had been established, encompassing a set of light reactions, with two different photochemical systems, which was linked to a light-independent sequence of dark reactions via a cyclic pathway. The paper outlines important milestones of this development, while it pays particular attention to the factors that drove the research in one direction or other.
18/09/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Pre-main sequence stars in clusters: from Orion to the Magellanic Clouds
Nicola Da Rio (ESTEC)

Abstract

The study of low mass, pre-main sequence (PMS) stars in clusters is critical for our understanding of the star formation process, and the initial mass function. Specifically, since PMS stars slowly contract towards the main sequence, they are natural tracers of the duration of star formation. Moreover, these objects are brighter than more evolved stars for the same mass, enabling us to detect them more easily well below the H-burning limit. Unfortunately, this is not without problems, and the uncertainties still remain large. I will describe some of my recent results in the field, focusing on the young stellar population in the Orion Nebula Cluster and in young regions of the Magellanic Clouds. I will mostly focus on issues and results related to the IMF in the very low-mass and brown dwarf regime, the long standing problem of the age spreads in young clusters, and the understanding of the time evolution of mass accretion rates.
11/09/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Probing the early stages of planet formation with ALMA and other sub-mm interferometers
Luca Ricci (Caltech)

Abstract

Observations of protoplanetary disks at sub-mm wavelengths trace mm-sized dust grains in the disk outer regions. Models of the early stages of planet formation, including growth and radial migration of dust grains in the disk, can therefore be tested by these data. I will outline the state-of-the-art of this field by presenting old and new data obtained with CARMA, PdBI, ATCA and EVLA interferometers for a large sample of young disks in nearby star forming regions. I will show how very-low mass disks are particularly suitable to test the model predictions and investigate the physics of solids evolution in disks. This is currently being investigated through undergoing observations with ALMA of four disks around brown dwarfs and very low-mass young stars. I will present the first results from this project and outline in which aspects future ALMA observations can play a key role in our understanding of planetesimal formation.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — The importance of the interactions between dust, comets and planets in planetary systems
Amy Bonsor (Institute of Astronomy, Cambridge UK)

Abstract

Dusty, debris discs are observed around hundreds of stars and there is an ever growing number of planet detections. In our Solar System it is clear that dynamical interactions between the planets, comets, asteroids and dust are important in sculpting its current structure and future evolution. It is clearly not possible to study the dynamics in such detail in exoplanetary systems, however, the evidence in support of the importance of such interactions is growing. In this talk I discuss two examples of observations that may be signatures of such interactions. Firstly, high levels of warm, exozodiacal dust, observed close to main-sequence stars. Such dust cannot have survived the star's lifetime in its current position and must originate from elsewhere in the planetary system. Secondly, observations of dust and metal pollution in white dwarfs, that are thought to be linked to evolved planetary systems.
03/09/12 (Monday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Workshop — ESO@50 - the first 50 years of ESO

August 2012

28/08/12 (Tuesday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — The Clump Mass Function of the Dense Clouds in the Carina Nebula
Stephanie Pekruhl (USM)

Abstract

In the Carina Nebula the feedback of the numerous hot stars disperses the parental Giant Molecular Cloud but also triggers the formation of new generations of stars. We obtained wide-field maps with the LABOCA camera at the APEX telescope, which provide the first spatially complete survey of the dust clouds in the Carina Nebula Complex and used the three common clump-finding algorithms CLUMPFIND, GAUSSCLUMPS and SExtractor to sample the Clump Mass Function (ClMF) in this region. To investigate the influence of the cloud temperatures on the ClMF we also assumed individual cloud temperatures for the clumps, resulting from an empirical relation between cloud column densities and temperature. In general we find a power-law of dN/dM ∝ M^(−1 .95), which is in good agreement with ClMF slopes found in previous studies of the ClMFs of other regions, but also that the shape of the resulting ClMF is highly dependent on the used extraction methods. While the CLUMPFIND ClMF is clearly described by a power-law the ClMFs based on the extractions with GAUSSCLUMPS and SExtractor are better represented by a log-normal distribution. This implies that the interpretations of a log-normal ClMF shape as a signature of turbulent pre-stellar clouds versus power-law ClMFs as a signature of star forming clouds only from observational determinations can be misleading.
14/08/12 (Tuesday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Triggered star formation and dispersal of molecular clouds by ionising radiation
Stefanie Walch (MPA)

Abstract

The role of feedback from massive stars is believed to be a key element in the evolution of molecular clouds. We use high-resolution 3D SPH simulations to explore the dynamical effects of a single O7 star located at the centre of a molecular cloud with mass 10^4M_sun and radius 6.4pc. The initial internal structure of the cloud is characterised by its fractal dimension, D=2.0 - 2.8, and its log-normal density PDF. (i) As regards star formation, in the short term ionising feedback is positive, in the sense that star formation occurs much more quickly in gas that is compressed by the high pressure of the ionised gas. However, in the long term ionising feedback is negative, in the sense that most of the cloud is dispersed with an outflow rate of up to ~0.01M_sun/yr, on a timescale comparable with the sound-crossing time for the ionised gas (~1-2Myr), and triggered star formation is therefore limited to a few percent of the cloud's mass. (ii) As regards the morphology of the ionisation fronts (IFs) bounding the HII region and the systematics of outflowing gas, we distinguish two regimes. For low D<=2.2, the initial cloud is dominated by large-scale structures, so the neutral gas tends to be swept up into a few extended coherent shells, and the ionised gas blows out through a few large holes between these shells; we term these HII regions "shell-dominated". Conversely, for high D>=2.6, the initial cloud is dominated by small-scale structures, and these are quickly overrun by the advancing IF, thereby producing neutral pillars whilst the ionised gas blows out through a large number of small holes between the pillars; we term these HII regions "pillar-dominated". (iii) As regards the injection of bulk kinetic energy, by ~1Myr, the expansion of the HII region has delivered a rms velocity of ~6km/s; this represents less than 0.1% of the total energy radiated by the O7 star. (iv) Last but not least, the distribution of triggered stars changes - from clustered to distributed - with increasing D.
07/08/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Herschel, Planck and the High Redshift Universe
David Clements (Imperial College London)

Abstract

The far-IR/submm band from 200 to 500 microns has been largely unexplored until very recently. Since their launch, in May 2009, Herschel and Planck have been exploring this waveband and providing new insights into a wide range of astrophysics. This talk focuses on the high redshift (z>1) universe and will discuss gravitational lenses, galaxy clusters and the search for the highest redshift dusty galaxies. It is still early days for the exploitation and followup of Herschel and Planck surveys, but it is already clear that these missions will have a major impact on our understanding of dusty galaxies at high redshift.

July 2012

31/07/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Exploring the Ursa Major Region
Kathrin Wolfinger (Swinburne University, Australia)

Abstract

The Ursa Major region is an ideal target to study the effect of environment on the evolution of gas-rich galaxies as it is nearby and most of the known member galaxies are late-type galaxies that are rich in neutral hydrogen (HI). We investigate 480 deg^2 and a heliocentric velocity range of 300-1900 km/s using data from the HI Jodrell All Sky Survey (HIJASS). The region includes the Ursa Major cluster (17.1 Mpc; Tully et al. 2008), the Canes Venatici groups (4.1 Mpc; Karachentsev et al. 2003) and the less dense filament connecting the Ursa Major and Virgo cluster (16.7 Mpc; Kent et al. 2007). I will present an overview of the region: (i) the peak-flux limited catalogue containing 155 HI sources, 13 of which are first time detections in HI including a candidate galaxy/tidal tail/HI bridge, (ii) intriguing objects such as HIJASS detections with HI extensions/plumes and (iii) candidate regions for galaxy-galaxy interactions. Furthermore I will show preliminary results from our study regarding substructures in the region and their dynamics.
26/07/12 (Thursday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy for Non-Astronomers
Talk — Hawaiian Starlight

Abstract

The summit of Mauna Kea (at >4000m) offers the best viewing of the Cosmos in the northern hemisphere, and this film delivers a pure esthetic experience from the mountain into the Universe.
25/07/12 (Wednesday)
11:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Special Talk
Talk — A History of Photosynthesis Research, 1840-1960
Karin Nickelsen (LMU)

Abstract

Today photosynthesis is known as the process by which green plants utilize the energy of sunlight to produce carbohydrates from carbon dioxide and water in the green parts of the plant. It is fundamental to life on earth, and the way organisms accomplish this task has intrigued scientists for centuries. The first tentative (and rather simplistic) ideas were developed by organic chemists around 1840, while by 1960 an elaborate photosynthesis model at a molecular level had been established, encompassing a set of light reactions, with two different photochemical systems, which was linked to a light-independent sequence of dark reactions via a cyclic pathway. The talk outlines important milestones of this development. While describing the process, however, it pays particular attention, first, to the factors that at different times were driving the research in one direction or other; and, second, to the transfer of knowledge (in terms of methods, mechanisms and concepts, across disciplines as well as across continents) as an important part of the actors' methodology. The history of photosynthesis research can be taken as a case in point for the beginning of large (interdisciplinary and international) research programmes, which is one of the reasons why this history is particularly interesting.
24/07/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — A near-infrared spectroscopic survey of star-forming galaxies and AGNs with Subaru/FMOS
John Silverman (Kavli Institute for the Physics and Mathematics of the Universe )

Abstract

I will discuss a new 'intensive' survey of star-forming galaxies in COSMOS using the Fiber Multi-object Spectrograph (FMOS) on the Subaru Telescope. FMOS is a multi-fiber instrument capable of simultaneously obtaining near-infrared spectra (1-1.8um) of a few hundred galaxies thus enabling a large redshift survey across a previously challenging redshift regime (1.2 < z < 1.8). Our survey is designed to detect Halpha in emission in order to establish the evolution of the SFR-Mstar relation and any dependence on environment. I will also highlight galaxies detected by Hershel/PACS and AGNs selected by their X-ray emission.
18/07/12 (Wednesday)
10:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Aberration Fields of Large Astronomical Telescopes: Finally, a complete understanding
Kevin Rolland-Thompson (Synopsys, Inc.)

Abstract

The performance of large astronomical telescopes is determined by the control of three aberrations, spherical, coma, and astigmatism. An understanding of these aberrations for the design of telescopes emerged with the work of many including Airy (1825), Coddington (1828), and Seidel (1860); culminating to some extent with Schwarzschild in 1905. However, a modern description of these aberration fields that accommodates the misalignment of the secondary (and tertiary) mirrors in 3-dimensions did not emerge until 1977 based on a discovery by Roland Shack inspired from a thru-focus star plate from Kitt Peak and an insight attributed to RA Buchroeder (1976). Thompson working with Shack’s initial insight went on to develop a complete understanding of aberration fields of misaligned optical systems (1980, 1985, 2005) and Schmid, Cakmakci, Rolland, and Thompson (2008-2009) that has come to be called Nodal Aberration Theory (NAT). However, this work did not accommodate mirror figure error. In 2009, Schmid, Rakich, Rolland, and Thompson found the path to include Primary mirror figure error, which is particularly relevant to the NTT, VLT, and VST telescopes with an active primary mirror. Most recently, Fuerschbach, Rolland, and Thompson (2012) have made a significant final addition that allows including secondary mount-induced figure errors (e.g. trefoil), providing a complete understanding of the aberration fields of actual telescopes in-use, including for example gravitational effects during a full sky track. This talk will provide the concepts and some of the new analysis methods that support understanding the alignment and figure status of the current generation of two mirror telescopes with active primary mirror figure control and the emerging generation of three mirror anastigmats, such as the JWST. Speaker: Kevin Thompson is an optical designer currently acting as the Group Director of R&D/Optics at Synopsys, Inc., the developer of CODE V and LightTools, to which he has made many contributions. He is also a visiting scientist at the University of Rochester, Institute of Optics, working with Prof. Jannick Rolland, The Brian J. Thompson (no relation) Professor of Optical Engineering, the Director of the RE Hopkins Center, and soon to be Director of the NSF Center for Freeform Optics, as well as appointments in Biomedical Engineering, The Center for Visual Science, and in France she is a Professor Invitée in the Institut D’Optique graduate school, Bordeaux. Kevin has a degree in astrophysics and physics in addition to a PhD in optical sciences. His most significant contribution to astronomy to-date has been the design and implementation of the null lenses that verified all of the optics that were the highly successful Hubble 1st Servicing mission. He has also led the optical design of advanced instrumentation for many leading astronomers including most recently an integral spectrometer for University of Florida. The application of NAT to telescope alignment was recently presented in PASP for the LSST telescope in an article led by Sebag [Sebag, J., W. Gressler, T. Schmid, J.P. Rolland, and K.P. Thompson, “LSST Telescope Alignment Plan Based on Nodal Aberration Theory”, PASP 124 380-390 (2012)].
17/07/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Physical properties of distant galaxies under the cosmic microscope
Johan Richard (CRAL, Observatoire de Lyon)

Abstract

I will present recent observational results obtained on the physics of distant galaxies (~ 1
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — The GAMA mass-metallicity relationship
Caroline Foster-Guanzon (ESO-Chile)

Abstract

We present the mass-metallicity relationship (MMR) of star forming galaxies in the Galaxy And Mass Assembly (GAMA) survey. The dependence of the MMR on intrinsic and apparent selection criteria is explored. We find that the shape and absolute position of the MMR in mass-metallicity space can be significantly altered by varying commonly used selection criteria. Implications for comparative studies of various surveys and redshifts are discussed.
13/07/12 (Friday)
10:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy Communication Seminar
Talk — Update on the activities of the IAU Global Office of Astronomy for Development
Kevin Govender (Director, IAU Global Office of Astronomy for Development, South Africa)

Abstract

On 16 April 2011 the International Astronomical Union's (IAU) Office of Astronomy for Development (OAD) was launched jointly by the President of the IAU and the South African Minister of Science and Technology, at the South African Astronomical Observatory in Cape Town. This OAD was set up to realise the IAU's strategic plan, which aims to use astronomy as a tool for development. Prior to this, on 29 March 2011 a presentation was made to ESO staff regarding the implementation plans for the OAD, as part of ESO's Astronomy Communication Seminars. This presentation will be a follow up to the 2011 one and an update will be given as to the progress of the OAD towards its vision of "Astronomy for a Better World".
12/07/12 (Thursday)
11:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy Communication Seminar
Talk — CFHT's Hawaiian Starlight: sharing the magic of Mauna Kea with the public
Jean-Charles Cuillandre (Canada France Hawaii Telescope Astronomer)

Abstract

The summit of Mauna Kea (at 14,000 feet) offers the best viewing of the Cosmos in the northern hemisphere, and the film "Hawaiian Starlight" (2009) delivers a pure aesthetic experience from the mountain into the Universe. Seven years in the making, this scenic film reveals the spectacular beauty of the mountain and its connection to the Cosmos through the magical influence of time-lapse cinematography scored exclusively (without narration) with the critically acclaimed Halo music by Martin O'Donnell and Michael Salvatori. Daytime and nighttime landscapes and skyscapes alternate with stunning true colour images of the Universe captured by the Canada France Hawaii Telescope on Mauna Kea, all free of any computer generated imagery. The lecture will present an overview of the making of the film and the images, followed by the screening of an extended segment.
11/07/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Why make such a fuss about the doubly magic nucleus Sn-100?
Thomas Faestermann (TUM)
10/07/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Exploring the phase space structure of the Milky Way halo with stellar orbits
Monica Valluri (University of Michigan)

Abstract

Resolved surveys of the Milky Way's stellar halo can obtain all 6 phase space coordinates of tens of thousands of individual stars, making it possible to compute their 3-dimensional orbits. The "orbital spectral analysis" technique can be applied to halo orbits to construct frequency maps which are a compact, yet informative representation of the halo phase space distribution function. Frequency maps visually represent the major types of orbit families that constitute the stellar halo and their relative importance. Analysis of simulations shows that even when halos are quite close to oblate, a large fraction of orbits have the characteristics of orbits in triaxial systems. The structure of the frequency maps, especially the resonant orbits, reflects the formation history and shape of the dark matter potential and its orientation relative to the Galactic disk. The application of frequency analysis to cosmological hydrodynamic simulations of disk galaxies shows that the orbital families occupied by halo stars and dark matter particles are very similar. An application of these methods to a sample of ~17,000 Milky Way halo stars from the SDSS-SEGUE-II survey yields a frequency map with strong evidence for resonant trapping of halo stars by the Milky Way disk. The observed resonances in frequency maps of SEGUE stars point to a fairly quiescent history for the Milky Way. The application of frequency analysis methods orbits of Milky Way halo stars (e.g. from the upcoming Gaia mission) will provide new insights into the formation history of the halo.
04/07/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Planck and the Cosmic Microwave Background
Torsten Ensslin (MPA)

June 2012

29/06/12 (Friday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy for Non-Astronomers
Talk — Food for a Monster
Stefan Gillessen (MPE)

Abstract

Using adaptive optics instruments on the VLT, a team of MPE scientists discovered in 2011 a gas cloud, which is falling straight towards the massive black hole in the centre of our Milky Way. The orbit of the cloud is well known, and the closest approach will happen in mid 2013. The cloud will not survive this. The tidal forces of the black hole will tear it apart, and additional destructive forces are expected from gas that is already present near the black hole. Ultimately, this cloud may feed the black hole, which might make it shine much brighter than today.
12:30, D29 | ESO Garching
Instrument Lunch Talk
Talk — VISTA/VIRCAM
Valentin Ivanov (ESO)
28/06/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Large Hadron Collider Project: status, highlight results and future prospects
Siegfried Bethke
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09:30, IPP-L130 (IPP, Garching) | ESO Garching
Talk — The Laser Tomography Adaptive Optics system of the Giant Magellan Telescope
Rodolphe Conan and Celine D'Orgeville (GMT project)

Abstract

The Giant Magellan Telescope (GMT) is one of the three Extremely Large Telescope programs. GMT is led by an international consortium of Universities and Science Institutes in the US, Australia and Korea. The Giant Magellan Telescope has an original design with a segmented primary mirror composed of seven individual mirrors, each 8.4m in diameter. Manufacturing of the segments has started with the first segment already completed and a second segment underway. GMT will be build at Las Campanas Observatory where site work has also recently begun. GMT has a rich Adaptive Optics (AO) program with 3 AO modes currently planned: Natural Guide Star AO, Laser Tomography AO and Ground Layer AO; all of them are in their preliminary design phase. After an overview of the GMT project, the presentation will focus on the LTAO system designed by the the Australian National University. Results of various trade studies regarding the design of the Laser Guide Star (LGS) wavefront sensors and the On-Instrument wavefront sensors will be exposed and the LGS facility, which has a lot in common with both the VLT and the E-ELT LGS facilities, will be discussed.
27/06/12 (Wednesday)
09:30, IPP-L130 (IPP, Garching) | ESO Garching
Workshop — ALMA Community Days 2012: Early Science in Cycle 1 - Tutorials
26/06/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Interaction of free-floating planets with a star-planet pair
Harry Varvoglis (University of Thessaloniki & University of Tübingen)

Abstract

The recent discovery of free-floating planets in the Milky Way introduced an intriguing possibility. Namely, that some exoplanets are not condensed from the protoplanetary disk of their parent star. In this novel scenario a free-floating planet interacts with an already existing planetary system and is captured as a new planet. In the present work we study this interaction process by integrating trajectories of planet-sized bodies, which encounter a binary system consisting of a Jupiter-sized planet revolving around a Sun-like star. The possible final outcomes of this interaction are only four, namely flyby, planet exchange, capture or disruption. We show that the process is a classical scattering problem with fractal properties. We find that the probability of exchange or capture (in prograde as well as retrograde orbits) is non-negligible, a fact that might possibly explain observations of planetary systems with orbits that are either retrograde or tight and highly eccentric.
09:30, Room 231/232 and IPP-L130 | ESO Garching
Workshop — ALMA Community Days 2012: Early Science in Cycle 1 - Tutorials
25/06/12 (Monday)
09:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Workshop — ALMA Community Days 2012: Early Science in Cycle 1
22/06/12 (Friday)
12:30, Room 232 (ESO HQ, Garching) | ESO Garching
Instrument Lunch Talk
Talk — MIDI
Markus Schoeller / Christian Hummel (ESO)
21/06/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Looking at the dark side: weak lensing by large scale structure
Henk Hoekstra (Sterrewacht Leiden)
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Abstract

Intervening structures in the universe give rise to small distortions in the shapes of distant galaxies. By measuring this tiny coherent signal, we can study the mass distribution in the universe directly, without relying on baryonic tracers. This makes weak lensing by large-scale structures a powerful probe of cosmology. It allows us to differentiate between dark energy models or modifications of the law of gravity. I will briefly review the topic of cosmic shear and discuss how the signal is extracted from the data and present results from the recently completed analysis of the CFHT Legacy Survey.

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20/06/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — The European Extremely Large Telescope
Jason Spyromilio (ESO)
19/06/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Shedding light on CANDELS
Audrey Galametz (Rome Observatory, INAF)

Abstract

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS; PIs: H. Ferguson, S. Faber; Grogin et al. 2011; Koekemoer et al. 2011) is the largest project in the history of Hubble (902 orbits). It will document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of ~250,000 galaxies with HST WFC3/IR and ACS. It will also permit to find the first Type Ia SNe beyond z > 1.5. CANDELS is currently observing 5 fields (selected for their existing multiwavelength data e.g. ground-based, Spitzer and spectroscopy), GOODS-N and GOODS-S, UDS, COSMOS and EGS at two distinct depths (a.k.a `CANDELS-Deep' and `CANDELS-Wide'). CANDELS is a collaboration of more than 100 scientists who will exploit the data to get insights on research topics as diverse as SN, Cosmic High Noon (26; e.g., constrain properties of galaxies at the end of the reionization epoch) etc. In this talk, I will (i) provide a brief overview on the CANDELS survey, (ii) describe observing strategy, data status and first results (iii) introduce the HAWK-I UDS and Goods-S survey (HUGS, PI: A. Fontana, follow-up of CANDELS with VLT/HAWK-I) (iv) present our team work to build public legacy multiwavelength catalogs for each CANDELS field and finally (v) present preliminary work on the search and study of large scale structures within CANDELS.
18/06/12 (Monday)
14:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Update on the E-ELT project
Adrian Russell, Alistair McPherson, Jason Spyromilio, Mark Casali (ESO)
15/06/12 (Friday)
12:30, D29 | ESO Garching
Instrument Lunch Talk
Talk — NaCo
Paola Amico / Lowell Tacconi-Garman (ESO)
14/06/12 (Thursday)
16:15, *** EXCEPTIONALLY IN THE MPE NEW SEMINAR ROOM, 1.1.18b *** | ESO Garching
Munich Joint Astronomy Colloquium
Talk — A modern look at galactic abundance gradients
Fabio Bresolin (IfA, Hawaii)

Abstract

The study of metallicity gradients in spiral disks has been a crucially important tool to understand the chemical evolution of galaxies. I will focus this talk on extragalactic gradients derived from young populations, and will briefly describe how observations of ionized nebulae (HII regions and PNe) and massive stars have shaped our understanding of the present-day radial distribution of metals in galaxies. I will highlight some recent developments in this field, in particular the study of gradients in outer galaxy disks and in galaxies at high redshift. I will conclude by introducing ongoing investigations of azimuthal metallicity variations and of gradients in low surface brightness galaxies.
12/06/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Co-evolving black holes and galaxies
James Mullaney (University of Durham)

Abstract

It is generally accepted that today's massive galaxies contain a central, supermassive black hole with a mass closely related to that of the host. However, how this situation has come about is far from clear. At some level, the growth of black holes and their galaxies must be linked, whether by active (e.g., direct feedback) or passive (e.g., common fuel supply) regulation. In this lunchtalk, I will highlight recent observational results which are beginning to shed light on how black holes and their host galaxies co-evolve and what processes may regulate their growth.
05/06/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Extra-Galactic Planetary Nebulae with Integral-Field Spectroscopy
Marc Sarzi (University of Hertfordshire)

Abstract

Planetary Nebulae (PNe) in external galaxies are mostly regarded either as tracers of the gravitational potential or as indicators for the distance of their galactic hosts, with the latter advantage owing to the almost universal - though not fully understood - shape of the PNe luminosity function (PNLF, generally in the [OIII]5007 emission). Yet extra-galactic PNe can also be used as probes of their parent stellar population and understanding in particular the origin of the PNLF is a puzzle that, once solved, promises to reveal new clues on the late stages of stellar evolution and on the formation of PNe themselves. I will show how integral-field spectroscopy allows to detect PNe in the optical regions of galaxies to flux levels otherwise inaccessible to standard narrow-band photometry. This allows to trace the PNLF in the same galactic regions where the properties of stellar populations can be well characterised, thus making it possible to understand how the shape of PNLF relates to the parent stellar population of PNe. I will present results based on the detailed analysis of SAURON data for M32 and M31, showing for the first time that the PNLF is in fact not universal, and preliminary work on galaxies as far as the Virgo cluster. I will also discuss the future prospect of this field with next generation integral-field units such as MUSE on VLT.
11:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Fundamentals of mm interferometry: Antennas, receivers, local oscillators, single-baseline interferometer, delays, correlator basics. Sensitivity
Robert Laing (ESO)

Abstract

This lecture is designed to explain how a modern radio array works, emphasising what you need to know in order to be able to process the data, rather than the details of the technology. ALMA will provide most of the examples, with some reference to LOFAR, EVLA and VLBI. The presentation follows the signal path from antenna to archive.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Multi-wavelength study of star formation in star-burst clusters
Giacomo Beccari (ESO)

Abstract

Planet formation theories are bound to comply with the current paradigm that protoplanetary discs appear to have lifetimes of ~3 Myr. This timescale is based on spectroscopic studies of circumstellar discs around pre-main sequence (PMS) stars located in low-density, nearby star forming regions. However, these objects do not reflect the conditions in place in the massive starburst clusters in which most stars form in the universe. Using a new robust method to identify PMS stars through their photometric excess in the Halpha band, we have studied the PMS population in several starburst clusters, namely NGC3603 in the Milky Way, 30 Doradus and the surrounding regions in the Large Magellanic Cloud and NGC 346 and NGC 602 in the Small Magellanic Cloud. I will present the main results of this research, including characterization of how PMS mass accretion rate scales with mass, metallicity and age. We found that there is a wide spread of ages (0.5 to 20 Myr) for PMS stars and that accretion from circumstellar discs continues well past 10 Myr. These results are bound to have important implications for theories of protoplanetary disc evolution and of star clusters formation in general.
01/06/12 (Friday)
12:30, Fornax (ESO HQ, Garching) | ESO Garching
Instrument Lunch Talk
Talk — X-Shooter
Joel Vernet / Vincenzo Mainieri (ESO)

May 2012

31/05/12 (Thursday)
12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy for Non-Astronomers
Talk — Venus in Sole Visa: The Transit of Venus
Davor Krajnovic (ESO)

Abstract

Venus in transit is a rare sight. The one this year is the last one in our lives, and a few of our children will see the next one. Today it is just about a planet going in front of the Sun, a little black dot on a bright disc for a few hours. Once, however, it was heralded as an unprecedented opportunity to measure the size of the Universe, but it turned out to be a disappointment. The story of Venus transits is also a story of science, how it went from an unorganised individualistic initiative to a complex social enterprise, where the scientific results are used to boost national pride and the public opinion controls the amount of money given to science. Venus transits prompted one of the first scientific expeditions, international competitions and collaborations. They motivated epic journeys across the world, from Arctic to Indian Ocean and the South Seas, bringing more discoveries about the Earth than about the Universe. The historic Venus transits remind us about the perseverance of astronomers in their pursuit of scientific results against weather, disease, war, political intrigues and personal tragedies. In this talk I will start by explaining the origin of this rare event and continue with an overview of historical transits highlighting the challenges and solutions, achievements and drawbacks, and the effects they had on the evolution of the science in a social context. This will be done by following a few astronomers in their chase across the world to see Venus in transit.
25/05/12 (Friday)
12:30, D30 | ESO Garching
Instrument Lunch Talk
Talk — VIMOS
Marina Rejkuba / Peter Hammersley (ESO)
24/05/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Matters of gravity: modified gravity and the Lisa Pathfinder mission
Joao Magueijo (Imperial College London)

Abstract

Contrary to popular belief, on very large distance scales visible matter stubbornly refuses to "fall" according to the laws of gravity of both Newton and Einstein. The paradox has led to the introduction of dark matter, purporting to explain the observed surplus of gravitational pull. The logical possibility remains that there is no dark matter, what you see is all there is, and that the paradox simply signals the break down of the Einstein-Newton theory of gravity. I will review alternative theories of gravity that do away with the need for dark matter. Surprisingly Solar system gravitational experiments, such as those associated with the LISA Pathfinder mission, might settle the score between the two approaches.
23/05/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Shell fragmentation and self-propagating star formation
Eva Ntormousi (USM)
22/05/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Dissecting the anatomy of the NGC 2264 G protostellar outflow with the Spitzer InfraRed Spectrograph
Paula Teixeira (University of Vienna)

Abstract

Bipolar molecular outflows and jets are natural by-products of star formation. These outflows deposit a significant amount of energy in their surroundings and help dissipate the circumstellar envelope of their protostar. I will present Spitzer observations of a powerful outflow in the young star forming region NGC2264, located ~900pc away. From the IRAC data, we found that the jet powering the outflow can be described by a precessing model, with a period of ~8000yr. Follow-up observations with the IRS detected atomic and ionic line emission from the underlying jet near the driving source, although most of the emission observed is from pure rotational H2 emission lines. We estimate that the H2 emission is arising from a mixture of gas with temperatures ranging between 1300 and 2500K. The morphology of the outflow, described by the S(0) and S(1) H2 emission is a textbook example of a bow shock and a nose cone, and we find a remarkable spatial correlation between these lines and low- and high-velocity components of the CO(2-1) outflow, respectively.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Spatially resolved infrared CO spectroscopy of Nearby Herbig Ae/Be stars
Miwa Goto (University Observatory Munich)

Abstract

The infrared CO vibrational transition lines are sensitive to the warm gas both in the disk inner-rim and the atmosphere of a protoplanetary disk. The angular resolution that one can achieve with an adaptive optics system at 8 m class telescope is 0".1 at the wavelength, which translates to ~10 AU at the nearest Herbig Ae/Be stars. We report a few new insights to the gas in the protoplanetary disks obtained by spatially resolved CO line spectroscopy of a group of nearby Herbig Ae/Be stars by CRIRES/VLT. The topics to be covered are as follows. 1) Detection of >400K gas at 50 AU away of a central star. 2) Testing the spatial profile of the line emission against the 'hot finger' gas disk model. 3) Comparative study of the disk atmosphere seen by CO in the group I and II Herbig Ae/Be stars.
16/05/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Closing in on the Higgs boson?
Sandra Kortner (MPP)
14:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy Communication Seminar
Talk — The GalileoMobile Documentary
Silvia Bonoli(1) and Sandra Benitez Herrera(2) ((1)MPA and Univ. Zurich; (2)MPA)

Abstract

This seminar is dedicated to GalileoMobile, an itinerant science education project whose main goal is to bring astronomy closer to young people in developing countries, particularly in areas that have little access to outreach programs. Sandra Benitez Herrera (MPA) and Silvia Bonoli (MPA and University of Zurich) will briefly introduce the project, summarising its objectives, up-to-date accomplishments and future prospects. They will then let participants enjoy the "Bajo un mismo cielo” (Under the same sky) documentary produced during the first expedition of the project. (Duration 50’) At the end of 2009 on a road trip that lasted two months and traveled over seven thousand kilometers in South America, GalileoMobile visited schools and communities in Chile, Bolivia, and Peru to perform science activities and organise astronomical observations. Through children's eyes, the documentary makes an encounter from different visions and interpretations of the sky, from East to West and from ancient times to modern astronomy, exploring the richness of human culture preserved in the traditions of the Andean people.
15/05/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Contemplating the Formation of Sun-like Stars
Doug Johnstone (National Research Council Canada, Herzberg Institute of Astrophysics)

Abstract

Coordinated multi-wavelength surveys of nearby molecular clouds provide useful constraints on the physical conditions within low-mass star-forming regions. In this manner, Perseus and Ophiuchus have been exceptional laboratories for testing the earliest phases of star formation. Highlights of these results are (1) most of the mass of the cloud is at low column density, (2) dense cores form only in high column density regions, (3) the mass distribution of the dense cores is similar to the that observed for stars, (4) dense cores contain only a few percent of the cloud mass, (5) the more massive cores are most likely to contain embedded protostars, and (6) the kinematics of the dense cores and the bulk gas show significant coupling. In this talk, I will mention each of these important results and attempt to place them in context with theoretical models and simulations of star formation.
10/05/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Debris disks in the Herschel era
Christoffel Waelkens (KU Leuven)
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Abstract

Debris disks are dusty disks orbiting mature stars. They owe their origin to collisional replenishment by small bodies and as such represent a major piece in the unfolding story of the nature of planetary systems. After their discovery by IRAS in 1982, their rich and diverse diagnostics have been studied by major ground-based facilities (VLT, VLTI, and, recently, ALMA) and space missions (HST, ISO, Spitzer). The role of Herschel is to offer for the first time the possibility to study their properties in the main domain in which they radiate their thermal energy, at an appreciable spatial resolution. Building on the important censuses Spitzer has achieved, Herschel has uncovered the anticipated existence of cold debris disks. We will discuss in detail the major results Herschel has achieved on nearby debris disks that can be well resolved spatially, in particular those of Vega, Beta Pictoris and Fomalhaut.

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09/05/12 (Wednesday)
10:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — Focal plane arrays and focal plane electronics for large scientific telescopes – new developments at Teledyne
Richard Blank (Teledyne)
08/05/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Triggering Quasars
Clive Tadhunter (University of Sheffield)

Abstract

We know surprisingly little about how, when and where quasars are triggered as galaxies evolve. In this seminar I will review quasar triggering mechanisms, and present the results from an optical and far-infrared study of a large sample of luminous radio-loud AGN that cast direct light on the quasar triggering issue, demonstrating that galaxy mergers are the most likely triggering mechanism. Along the way, I will emphasise the importance of taking full account of the AGN-related continuum components when determining the host galaxy properties.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Disks, Accretion and Outflows of Brown Dwarfs
Emma Whelan (Dublin Institute for Advanced Studies)

Abstract

Interestingly, brown dwarfs with masses down to a few Jupiter masses have been found to exhibit accretion and outflow activity reminiscent of what is observed in low mass stars. As the exact formation for brown dwarfs is still under debate it is important to properly characterise accretion/ejection activity in these substellar objects. In this talk I will summarize what has been learnt so far in relation to accretion/ejection connection in young brown dwarfs. As classical T Tauri stars are considered touchstones for models of accretion/ejection in young stars comparison is often made between brown dwarfs and T Tauri stars. I will outline what observational constraints can be made on models of brown dwarf formation and describe how future work will be influenced by the development of new instruments such as X-Shooter on the VLT.
03/05/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Galaxy-Halo Connection Across Mass and Time
Risa Wechsler (KIPAC / Stanford University)
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11:00, D29 | ESO Garching
Talk — Fundamentals of mm interferometry: Coherence, basic equations, simplifications - narrow bandwidths, small fields - and Fourier transform basics
Robert Laing (ESO)
02/05/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Understanding neutrinos? GERDA and the neutrinoless double beta-decay
Bela Majorovits (MPP Freimann)

April 2012

25/04/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Constraints on gravity, dark energy, cluster astrophysics, and neutrino properties from galaxy clusters
David Rapetti (Dark Cosmology Institute, Denmark)
24/04/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Extragalactic molecular line surveys
Rebeca Aladro (University College London)

Abstract

Molecular line surveys are excellent tools to study the physical chemical properties of the extragalactic interstellar medium. Recent studies have demonstrated that molecular abundances in the nuclei of galaxies can be used to disentangle the deeply obscured nuclear power sources (AGN or starbursts), as well as to estimate the strength of the UV fields, X rays, and/or shocks affecting the gas. I will review the most important studies done on this field, and show how the physical properties of the ISM can be derived from this chemical studies.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Evidence of a low star formation rate in the Central Molecular Zone despite recent star formation outbursts
Katharina Immer (MPIfR)

Abstract

The Central Molecular Zone (CMZ) is a place with extreme conditions in our Galaxy, the temperature, velocity dispersion and pressure values are much higher than in the Galactic disk. From a statistical point of view, a star formation study in the CMZ can uncover if star formation in this region is enhanced or suppressed by these extreme conditions compared to other parts of the Galaxy. I will present 5-40 micron Spitzer/IRS spectroscopic observations of a sample of 68 ISOGAL sources with unknown natures. These sources were selected to test ISO color selection criteria. Based on their spectral features and the slope of their spectra, the sources were classified as young or late-type evolved objects. We applied the color selection criteria to all ISOGAL sources in the CMZ, selecting 485 young object candidates, and added 656 MSX young object candidates with F_E/F_D > 2 to the CMZ sample. The bolometric luminosities and subsequently the masses of the sources in the CMZ sample were determined. Applying a Kroupa initial mass function, the total mass in young objects that has been formed over the last 1 Myr was derived, yielding an average star formation rate of 0.08 solar masses per year for the CMZ. This result shows that, despite recent star formation outbursts, the star formation rate in the CMZ is at least a magnitude lower than the global star formation rate in the Milky Way.
19/04/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Dusty Nature of Quasars
Bozena Czerny (Copernicus Astronomical Center, Warsaw )
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Abstract

The most characteristic property of active galaxies, including quasars, are prominent broad emission lines. These lines allowed to discover the cosmological nature of quasars, and at present they provide the most convenient method of weighting black holes residing in their nuclei. However, a question remains why such strong lines form there in the first place. I will discuss an interesting possibility that dust is responsible for this phenomenon. The dust is known to be present in quasars in the form of a dusty/molecular torus which results in complexity of the appearance of active galaxies. However, this dust is located further from the black hole than the Broad Line Region. We propose that the dust is present also closer in and it is actually responsible for formation of the broad emission lines. The argument is based on determination of the temperature of the disk atmosphere underlying the Broad Line Region: it is close to 1000 K independently from the black hole mass and accretion rate of the object. The mechanism is simple and universal but leads to a considerable complexity of the active nucleus surrounding. I will conclude with the discussion how this idea fits into the general scheme of the quasar structure.

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12:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Lunch Talk
Talk — Diffuse mid-IR emission: A problem for SFR measures?
Alison Crocker (University of Massachusetts)

Abstract

Emission in the mid-IR (3-30 micron) in star-forming galaxies is mostly due to emission from small dust grains and large molecules. The large molecules, PAHs, emit in several bright bands, while both the large molecules and small grains emit continuum emission, after being heated to high effective temperatures by one or few photons (stochastic heating). These small particles have higher absorption cross-sections in the UV than classical (large) dust grains, theoretically making them a better tracer of young stars than the big grains which are more easily heated by lower-energy photos produced by older stars. However, they might be a less ideal tracer than hoped for due to two factors (1) the small grains/large molecules are largely destroyed in the vicinity of hot, young stars and (2) despite the UV-biased cross-section, the small grains/large molecules may be excited by old stars as well as young stars, particularly when located far from star-forming regions. Here I present work on a few, nearby, star-forming galaxies. By spatially separating the star-forming and non-star-forming regions and taking into consideration both UV photons and stars themselves "leaking" from star-forming regions, the fraction of 8micron dust emission due to old stars is approximately 40%, a large enough fraction to worry about this contribution when considering its use as both a low-redshift (typically resolved) and a high-redshift (at z=2 is in the MIPS 24 micron band) SFR measure. I will also discuss the decline of the 8micron to Halpha emission ratio in both star-forming and diffuse regions, discussing some (metallicity-dependent) reasons for the trends we see.
17/04/12 (Tuesday)
14:00, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — NAOMI - the adaptive optics system for the ATs
Emmanuel Aller Carpentier (ESO)

Abstract

I will present the preliminary baseline concept of NAOMI, the future adaptive optics system for the Auxiliary Telescopes (ATs, 1.8 m diameter) of the VLTI. Currently the ATs are equipped with a fast, visible tip-tilt sensor called STRAP, and the corrections applied through a tip-tilt mirror. This gives a good correction of the atmospheric turbulence in K and N bands for good seeing conditions, but insufficient for seeing beyond 1’’ specially in J band. In the context of the new VLTI instruments it has been decided to replace STRAP and the sterring mirror with a low-order adaptive optics system (SCAO), ‘’NAOMI’’ consisting in a SHS wavefront sensor and a deformable mirror. The new AO system will ensure better energy injection on the fiber avoiding PSF explosion and therefore allowing VLTI instruments operation under shorter wavelengths.
12:30, D29 | ESO Garching
Lunch Talk
Talk — Type Ia Supernovae: Explosions and Progenitors
Wolfgang Kerzendorf (University of Toronto)

Abstract

Type Ia supernovae are known as the precise distance indicators that allowed the remarkable discovery of the accelerated expansion of the universe. Despite this astounding feat, there still remain large uncertainties in many of the key issues surrounding these extremely energetic events. These uncertainties, while not being horribly detrimental to their use as distance indicators, hamper the understanding of the far reaching consequences these cosmic factories of heavy elements have on the chemical evolution of the Universe. Type Ia Supernovae can be divided into three distinct phases. The pre-supernova evolution, the explosion itself and the expansion phase, which results in spectra and light-curves. In this talk I will first presents our findings on the progenitor question (pre-supernova phase). In addition, I will discuss my work on automating spectral analysis and how it links with explosion physics and the progenitor question. Finally, I will briefly highlight Universities of Toronto's involvement in arctic astronomy and introduce our transient search with the telescope CATS.
12/04/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Feedback Processes in Rapidly Star-Forming Galaxies
Todd Thompson (Ohio State University)
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10/04/12 (Tuesday)
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Structure of accretion and outflow on small scales in high-mass protostars
Ciriaco Goddi (ESO)

Abstract

Very Long Baseline Interferometry observations of molecular masers has been proved to be a unique tool to study the 3D kinematics of molecular gas in the proximity of massive young stellar objects (YSOs), probing expansion in jets/outflows (H2O) and rotation/infall in disks/envelopes (CH3OH). I will describe our findings towards two targets which revealed two different patterns: I) an intermediate-mass (possibly pre-ZAMS) YSO drives a radio jet which excites H2O masers in a "collimated" bipolar flow; CH3OH masers show that gas accretion onto the YSO is still ongoing. II) an O-type (ZAMS) YSO excites a hypercompact (HC) HII region, which lies at the center of an arc-like distribution of H2O masers and drives a "wide-angle" flow, while CH3OH masers probe gas outside the HII region that may no longer accrete onto the YSO. I will briefly describe an observational program whose key goal is to assess if the different patterns of ejection/accretion we observed is a typical signature in the evolution of massive YSOs. This may enable to address two key questions in massive star formation: 1) Does outflow collimation decrease with protostellar mass or age? 2) Can mass-accretion proceed once a HC HII region has formed?
03/04/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Interstellar polarization: old models and new ideas
Nikolai V. Voshchinnikov (St. Petersburg University, Russia)

Abstract

Interstellar linear polarization is caused by the linear dichroism of the interstellar medium due to the presence of non-spherical oriented grains. The interpretation of polarimetric observations includes computations of the polarization cross sections and averaging of them for given particles size and orientation distributions. Early models dealt with infinite cylindrical particles which were assumed to be perfectly aligned. Such models produce polarization much larger than the observed one. We use the model of spheroidal grains with imperfect alignment. It allows one to estimate the properties of dust grains and the angle between the line of sight and the magnetic field direction, i.e., to find the space structure of magnetic field. The results for Taurus molecular cloud TMC-1 will be demonstrated. The nature of polarizing grains can be established from the comparison of the degree of interstellar polarization P and polarization efficiency P/E(B-V) or P/A(V) with dust phase abundances. We detect an anticorrelation between P and the dust phase abundance of iron in non silicate-containing grains, a correlation between P and the abundance of Si, and no correlation between P/E(B-V) or P/A(V) and dust phase abundances. These findings can be explained if mainly the silicate grains aligned by the radiative mechanism are responsible for the observed interstellar linear polarization.

March 2012

29/03/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Precision Array to Probe the Epoch of Reionization
Chris Carilli (NRAO)
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27/03/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Nuclear clusters in late-type dwarf galaxies in low-density environments
Iskren Georgiev (AIfA, Bonn)

Abstract

Massive star clusters in the nuclear regions of dwarf (irregular) galaxies have been envisioned as possible progenitors of a sub-population of peculiar Galactic globular clusters, e.g. wCen, NGC 2419, M54. The latter is still associated with the nucleus of the dissolving Sagittarius dSph. It is however not well known, how the properties of massive nuclear clusters in such dwarf galaxies compare to those of these Galactic GCs. A common origin, i.e. in a deep potential, will result in a similar evolution of their stellar populations and structural properties. I will present such an analysis based on a large sample of nuclear clusters in dwarf irregular galaxies studied with HST imaging and VLT spectroscopy and supplemented by new (still in progress) analysis of B,V,I VIMOS imaging of 10 LMC mass dIrrs, located in the outskirts of Fornax and Eridanus galaxy clusters.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Warm gas atmospheres of the protoplanetary disks seen by Herschel: Gas rich and carbon poor?
Simon Bruderer (MPE)

Abstract

With the Herschel Space Observatory, lines of simple species ([CII], [OI] and high-J lines of CO) have been detected in the atmosphere of protoplanetary disks. When combined with ground-based data on [CI] all principle forms of carbon can now be studied. This allows to test model predictions for the main carbon bearing species to study the gas-phase carbon budget and the presence of a warm surface layer. I present new thermo-chemical modeling of the well studied disk around the Herbig Be star HD 100546. Using this model, we can reproduce the CO ladder (J = 3 − 2 to 30 − 29) together with the atomic fine structure lines of [OI] (63 and 145 μm) and either [CII] (158 μm) or the upper limit of [CI] (370 μm). We find that the high-J lines of CO can only be reproduced by a warm atmosphere with a gas temperature much increased over the dust temperature. The low-J lines of CO, observed from the ground, are dominated by the outer disk with radius of several 100 AU while the high-J CO observable with Herschel-PACS are dominated from regions within some tens of AU. The profiles of high-J lines of CO are predicted to be broader than the low-J lines. We study the effect of several parameters including the size of the disk, the gas mass of the disk, the PAH abundance and distribution and the amount of carbon in the gas phase. The absence of neutral carbon [CI], which is predicted to be strong by thermo-chemical models, is discussed in the context of the gas-phase carbon budget.
22/03/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Three Freaks of the Solar System (And Why They Matter)
Dave Jewitt (University of California)
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Abstract

In addition to the major planets, the solar system contains a large number of so-called small bodies in dynamically distinct reservoirs. These include the main-belt asteroids, main-belt comets, Trojans, Centaurs, irregular satellites, the comets of the Oort cloud and Kuiper belt, and others. These reservoirs are important both for the relics of solar system formation contained therein, and as sources for short-lived populations in the inner solar system. For the most part, the small body populations were discovered recently, their investigation is still firmly in the exploration phase and much of the excitement in planetary science stems directly from them. I will use new observations of three "freak" and very surprising objects as a vehicle to discuss the small body populations, to highlight our ignorance of even basic issues in the origin and evolution of the solar system, and to indicate potentially productive paths to future research.

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20/03/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — News from the merger remnant NGC 1316 (Fornax A)
Tom Richtler (Universidad de Concepcion, Chile)

Abstract

I shall present results from recent photometric and spectroscopic work on the merger remnant NGC 1316 and its globular clusters (GCs). Wide-field imaging in the Washington system reveals morphological details which previously have gone unnoticed. The distribution of GC colors indicates an extended period of star cluster formation. The kinematics of about 170 GCs show a complex behavior, complicating a dynamical analysis. Finally, I briefly present the remarkable object SH2 in NGC 1316 which may be an infalling dwarf galaxy.
15/03/12 (Thursday)
16:15, *** EXCEPTIONALLY IN THE MPE NEW SEMINAR ROOM, 1.1.18b *** | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Using stellar mass black holes to understand AGN
Chris Done

Abstract

I will review the spectral and timing properties of x-ray binaries, especially the behaviour seen as the source makes a transition from the low/hard to high/soft state. The broad band spectral evolution is well modelled by a truncated disc/hot inner flow geometry, where the truncation radius moves progressively towards the last stable orbit during the transition. Here I show that this same geometry can also quantatitively match the power spectral evolution, where fluctuations propagating through the hot flow (stirred up by the MRI) make the broad band continuum power spectra, and Lense-Thirring precession of the hot flow makes the prominent low frequency QPO. I will then take some of the insights on accretion in stellar mass black holes and see how they can help in interpreting AGN spectra.
13/03/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Density waves in debris disks
Mir Abbas Jalali (Sharif University of Technology)
08/03/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Feedback from Accreting Black Holes: The Importance of Momentum Driving
Jerry Ostriker (Princeton University)
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Abstract

Black holes, resident in the centers of galaxies, will be fed by accretion of ambient gas whenever gas reaches those central regions. This can be due to mergers, but even without mergers the evolution of the stellar populations of normal galaxies provides very large amounts of gas, as stars pass through the planetary nebula stage, the total mass release being greater than 10$^{11}$ Msolar for massive ellipticals. Much of that gas will cool and fall to the centers of the systems, where it will induce starbursts and accretion events onto the central black holes. Accretion then induces outbursts of UV from the BH discs, Xrays from coronal gas and polar, radiation driven winds, with the efficiencies in these three categories roughly 10$^{-1}$, 10$^{-2}$ and 10$^{-3}$. The mass, momentum and energy in these outbursts can have dramatic consequences for the growth of the BH and for the ambient galaxy. Most AGN feedback treatments do not include the mass and momentum components. We follow these events with 1D, 2D and 3D hydrodynamic codes. BH growth is similar to what has been found by others, but the momentum driving produces much more energetic winds than does thermal feedback. Observable consequences include the narrow line AGN absorption lines, shock accelerated synchrotron emitting particles and wind driven bubbles in the IGM. In addition, we find that the feedback strongly inhibits inflow, causing episodic accretion and a low "duty cycle". The simulations help us to understand many phenomena including the black hole stellar mass relation, the paucity of gas in ellipticals, the incidence of the ¡°E+A¡± phenomena and the observed fact that most of the black holes found in galactic centers are found in the "off" state.

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06/03/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — The MIDI AGN Large Programme: A statistical sample of resolved AGN tori
Leonard Burtscher (MPE)

Abstract

Interferometric observations with MIDI/VLTI in the mid-infrared made studies of the central dusty tori of Active Galactic Nuclei (AGNs) possible and proved their existence in a number of nearby galaxies. Both type 2 and type 1 galaxies showed dust on the parsec-scale whose general properties were comparable - consistent with (but not proving) the "unifying model" for radio-quiet galaxies. Existing studies were, however, mostly based on single or very few sources and therefore dominated by the characteristics of individual galaxies. For a more comprehensive approach, a larger sample is needed. This statistical basis is set up as a VLTI/MIDI Large Programme that comprises 14 AGNs for which torus properties are being determined. Observations and data reduction are finished and show resolved dust emission in almost all of the sources. They represent the largest sample of resolved AGN tori so far, allowing to ask a number of questions, ranging from unification to the physics of accreting galactic nuclei. In particular, the observations allow us to dissect the parsec-scale infrared emission and to determine the sizes and fluxes of the various components.
01/03/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Thermonuclear supernovae from different progenitor systems
Friedrich Roepke (Univ. Wuerzburg)
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Abstract

Thermonuclear explosions of white dwarfs are thought to explain Type Ia supernovae (SNe Ia) -- but it is still unclear how these explosions come about and how they proceed in detail. This is a fundamental problem as SNe Ia are key players in many fields of astrophysics including galactic chemical evolution and observational cosmology. Since their progenitors elude observation as well as modeling, I will argue that simulations of explosions arising from different scenarios can help to overcome the problem. A new generation of three-dimensional hydrodynamic explosion simulations in combination with radiative transfer calculations allows us to predict observables that can be directly compared to astronomical data. Avoiding tunable parameters in the models, conclusions on progenitor properties are possible. Contradicting 'textbook wisdom', recent results demonstrated that a normal SN Ia does not necessarily require the explosion of a Chandrasekhar-mass white dwarf, but they also do not rule out this possibility. While the question of the progenitor channel responsible for the bulk of objects remains open, the synthesis of modeling and recent observations underpins the emerging picture of SNe Ia being much less homogeneous than previously thought. This could complicate their use as cosmic distance indicators.

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February 2012

28/02/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Properties of the AGN wind of Mrk 509
Katrien Steenbrugge (Universidad Catolica del Norte en Antofagasta, Chile)

Abstract

I will present the optical, UV and X-ray data obtained during a 3 month observational campaign of the Seyfert 1 galaxy Mrk 509, using 5 different satellites, and obtained with the goal to determine the mass, kinematic luminosity and feedback on the host galaxy of this outflow. I will focus on the 600 ks XMM-Newton RGS spectrum, which is the deepest high-resolution X-ray spectrum yet of a Seyfert 1 galaxy, and the high signal-to-noise HST-COS UV spectrum. The excellent statistics allow us to study in detail the ionization structure and relative abundances (X-rays) and kinematics (UV) of this gas. The ionization structure spans 3 orders of magnitude and is discrete and the abundance ratios are consistent with solar ratios. We detect absorption from an AGN wind which has 8 different kinematic components and is located at distances between 5 and 400 pc; the host galaxy and probably a high velocity cloud about 22 kpc from Mrk 509.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — EX Lupi from quiescence to outburst - a study of the molecular gas MIR emission from disks affected by star variability
Andrea Banzatti (ETH Zurich, Inst. f. Astronomy)

Abstract

In recent years the study of gas in young circumstellar disks has been rapidly growing, especially in relation with an increasing interest in disk evolution processes and in the presence of molecules relevant for life at disk radii where planets are expected to form. In this talk I will present an analysis of the MIR emission from molecular gas (in particular H2O, OH, HCN, C2H2, CO2) observed in the strongly variable T Tauri system EX Lupi. We compared archival Spitzer spectra taken before and during an exceptional outburst happened in 2008 to see if and how the gas in the inner few AUs of the circumstellar disk is affected by a sudden large increase in the stellar+accretion luminosity. I will describe the method we developed and highlight the main results, as well as discuss the limitations and the new perspectives provided by this analysis. In an attempt to address some of them, in the conclusion I will mention the further investigations that I am currently undertaking using the powerful modern instruments available at the ESO VLT.
23/02/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — A gas cloud on its way towards the supermassive black hole at the Galactic Centre
Stefan Gillessen (MPE)
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Abstract

Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares Sgr A* is surprisingly faint, suggesting that the accretion rate currently is very low. In 2011 we discovered a dense gas cloud approximately three times the mass of Earth that is falling into the accretion zone of Sgr A*. Our observations fully constrain the cloud's orbit. It is highly eccentric with a pericenter distance of only 3100 times the Schwarzschild radius. The pericenter passage will happen in summer 2013 and already now we can see that the cloud has begun to tidally disrupt due to the black hole's gravitational force. The cloud also is a probe for the properties of the accretion flow, and ultimately we might have a chance to see how a massive black hole is being fed.

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15/02/12 (Wednesday)
17:00, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Spectral energy distribution of heavily obscured AGN beyond the local Universe
Italo Balestra (INAF Trieste)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Galaxy (and) cluster formation at redshift z=2
Raphael Gobat (CEA Saclay)
14/02/12 (Tuesday)
10:00, D29 | ESO Garching
Star and Planet Formation Seminar
Talk — Surface photometry of nearby galaxies with VST
Massimo Capaccioli (INAF - Capodimonte, Napoli)

Abstract

The VST + OmegaCam wide-field facility has come into operation at Paranal and we have just started the analysis of the first images of the nearby elliptical galaxies selected for the VEGAS survey. In particular we have fully reduced, using the pipeline VST-tube developed at Naples, the images of the giant NGC 1399 in Fornax taken in g, r and i bands. In the talk I will shortly report on the quality of the material, on the difficulties met during the reduction, and on the solutions adopted to overcome them. I will show comparisons with previous studies both for the galaxy light distribution and for the luminous extended halo (ICL), with hints to color gradients, and I shall report on a comparison made with the GCs of the galaxy observed by HST.
09/02/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Super-Earths and Neptune-mass planets from the HARPS surveys: a window to planetary-system diversity
Stephane Udry (University of Geneva)

Abstract

I will report on the results of an 8-year survey carried out at the La Silla Observatory with the HARPS spectrograph to detect and characterize planets in the super-Earth and Neptune-mass regime. The size of our star sample and the precision achieved with HARPS have led to the detection of a sufficiently large number of low-mass planets to study the statistical properties of their orbital elements, the correlation of host-star properties with the planet masses, as well as the occurrence rate of planetary systems around solar-type stars. These results will be discussed in comparison with equivalent results obtained in our M-dwarf survey and with the recent Kepler findings.
10:00, Fornax (ESO HQ, Garching) | ESO Garching
Euclid Journal Club
Talk — A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope Infrared Observations from CANDELS, by Rodney et al.
Bruno Leibundgut (ESO)

Abstract

This is a fairly short paper, but it is the first from the multi-cycle HST program to find the most distant supernovae. I will expand on that a little bit as well.

08/02/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Experimental studies of strong interaction in exotic atoms
Oton Vazquez-Doce (TUM)
02/02/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The power of gravity-mode oscillations to probe the physics of stellar cores
Conny Aerts (KU Leuven)
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Abstract

The CoRoT and Kepler space missions, while still ongoing, already revolutionised our view on stellar pulsation. After a very brief introduction in asteroseismology, we illustrate how the immense advantage of having long-term uninterrupted data from space with a factor 100 better precision compared to data from the ground implies large progress in the tuning of stellar physics. In particular, we focus on some cases where gravity-mode oscillations were detected in addition to acoustic modes and show how this allowed modelling of the near-core regions in stars. We end by highlighting future prospects based on the continuing data gathering by both missions while pointing out some challenging issues in the theory of stellar structure that need to be resolved to properly interpret the space data.

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12:30, Fornax (ESO HQ, Garching) | ESO Garching
Talk — An atmospheric piston simulator for LINC - NIRVANA
Roman Follert (MPIA, Heidelberg)

Abstract

LINC - NIRVANA (LBT INterferometric Camera - Near-IR / Visible Adaptive iNterferometer for Astronomy, LN) will demonstrate image plane interferometry with a wide field of view. This will, for the first time, allow imaging with the spatial resolution of a telescope with a 23 m aperture. This ambitious goal imposes serious requirements on the AO and fringe tracking systems of LN. Therefore, dedicated testing and verification experiments during integration are mandatory. In that respect, it will be beneficial to mimic the environmental conditions at the observatory site (Mt. Graham, Arizona) as realistically as possible. For this purpose, I designed and assembled an atmospheric piston simulator. Due to its optical fiber based design, there are various interfaces for the integration into LN. Furthermore, the piston simulator is controlled such that piston sequences of arbitrary complexity are generated. The atmospheric piston simulator will be used in near future to verify the LN fringe tracking system. In this talk, I will introduce the design, the respective control schemes, and the results of the lab verification experiment of the atmospheric piston simulator.
01/02/12 (Wednesday)
16:30, Cluster Building, Boltzmannstr. 2, Garching | ESO Garching
Cluster Universe Colloquium
Talk — Dust in the wind - Grain growth and transport in protoplanetary disks
Til Birnstiel (LMU)

January 2012

31/01/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — The Star Formation & Chemical Evolution Timescales of Two Nearby Dwarf Spheroidal Galaxies
Thomas de Boer (Kapteyn Astronomical Institute, Groningen)

Abstract

We present the detailed Star Formation History of the nearby Sculptor and Fornax dwarf spheroidal galaxies, from wide-field photometry of resolved stars, going down to the oldest Main Sequence Turn-Off. The accurately flux calibrated, wide-field Colour-Magnitude Diagrams are used directly in combination with spectroscopic metallicities of individual RGB stars to constrain the ages of different stellar populations, and derive the Star Formation History with particular accuracy. The detailed Star Formation History shows the star formation at different ages and metallicities, at different positions in the galaxy, and shows that the known metallicity gradients are well matched to an age gradient. The obtained SFH is used to determine accurate age estimates for individual RGB stars, for which spectroscopic abundances (alpha-elements, r- and s-process elements) are known. In this way, we obtain the accurate age-metallicity relation of each galaxy, as well as the temporal evolution of alpha-element abundances. This allows us to study, for the first time, the timescale of chemical evolution in these two dwarf galaxies, and determine an accurate age of the "knee" in the alpha-element distribution. Finally, we compare the timescale of chemical evolution in both dwarf galaxies, and determine whether the chemical abundance patterns seen in galaxies with recent episodes of star formation are a direct continuation of those with only old populations.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — The link between turbulence, cloud structure, and star-formation
Nicola Schneider (CEA Saclay / Observatoire de Bordeaux)

Abstract

Interstellar turbulence plays a major role during the formation process of molecular clouds and stars. I will review observational signatures of turbulence (filamentary structure of molecular clouds, Delta-Variance, probability density functions) and its link to star-formation. Recent observational data (continuum and molecular lines) from Herschel, Spitzer, SOFIA, and ground-based submm-radiotelecopes will be presented. In particular the new Herschel FIR photometric maps (70-500 micron) of Galactic clouds obtained within several programs (HOBYS, Gould Belt, Hi-GAL) allow for the first time to derive a large set of precise column density and temperature maps that allow to trace the cloud structure and the content of Young Stellar Objects at the same time. Combining Herschel continuum data with (sub)-mm molecular line data is essential to study the velocity structure of the clouds and to compare with numerical models. Preliminary results for the Rosette Cloud indicate that star-formation is mainly determined by large-scale turbulence that defined a primordial density structure, and not by UV-radiation. A study of the Cygnus region shows that it is due to high accretion rates, provided by filaments, that explain cluster formation.
27/01/12 (Friday)
13:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Talk — The astronomy technology program at the National Research Council of Canada Herzberg Institute of Astrophysics (NRC-HIA)
David Loop (NRC-HIA)

Abstract

An overview of the astronomy technology program at the National Research Council of Canada Herzberg Institute of Astrophysics (NRC-HIA) will be presented. The talk will outline HIA capabilities and organization, the Canadian Long Range Plan (LRP) for Astronomy, and the current and future observatories we are partnered with. Current development projects include ALMA Band 3 and Band 1 cryogenic receivers, SKA correlator, composite antennaes, low noise amplifiers, and phased array feeds, TMT NFIRAOS adaptive optics, IRIS science instrument, and project office roles, Gemini GHOS high resolution optical spectrograph and GMOS focal plane arrays, CFHT SPIRou infrared high resolution spectrograph. Current research projects include RAVEN multi-object adaptive optics demonstrator, adaptive optics test bench, Canadian Arctic observatory, CCAT CHAI heterodyne array, CHIME hydrogen mapping experiment, and next generation CFHT observatory.
26/01/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Galaxy Build-up and Evolution at z>=7: Results from ultra-deep WFC3/IR observations over the HUDF, GOODS, and CANDELS fields
Rychard Bouwens (Leiden University)

Abstract

The new WFC3/IR camera aboard HST enables us to survey the sky in the near-IR 40x more efficiently than ever before -- allowing for enormous progress in both the search and characterization of very high-redshift galaxies. Already in the first two years of observations, we have deep and ultra-deep observation over >200 arcmin**2 in legacy fields like the HUDF and GOODS and now CANDELS. With these data, we have been able to select large number of very high-redshift galaxy candidates -- over 150 galaxies at z>=7 including one possible z~10 galaxy -- and study their properties in substantial detail. These new selections have allowed us to quantify the evolution of the UV LF and faint-end slope from z~10, significantly constrain the stellar populations and dust properties of z~5-8 galaxies, and construct a general picture of how galaxies build up early in the universe and how it may have been reionized. In this presentation, I provide a summary of our current results and the picture which is emerging.
25/01/12 (Wednesday)
11:30, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Astronomy Communication Seminar
Talk — Outreach at the International Space Science Institute in Bern, Switzerland
Prof. Rudolf von Steiger (Director, ISSI, Bern)

Abstract

The International Space Science Institute (ISSI) is an Institute of Advanced Studies where scientists from all over the world meet in a multi- and interdisciplinary setting to reach out for new scientific horizons. The main function is to contribute to the achievement of a deeper understanding of the results from different space missions, ground based observations and laboratory experiments, and adding value of those results through multidisciplinary research in the framework of International Teams, Workshops, Working Groups, Forums or as individual Visiting Scientists. The program of ISSI covers a widespread spectrum of disciplines from the physics of the solar system and planetary sciences to astrophysics and cosmology, and from Earth sciences to astrobiology. We will present an overview of ISSI and its mission in general and focus on our efforts in public outreach, mainly to trigger a discussion about the experience of ESO in that respect and learn from it.
19/01/12 (Thursday)
16:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Galaxy Mergers through Cosmic Time
Jennifer Lotz (STScI, Baltimore)
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Abstract

Galaxies grow with time through both discrete galaxy mergers and smooth gas accretion. When and how this growth occurs, and the role of mergers in defining the properties of today's galaxies, remain outstanding observational questions. Observational estimates of the galaxy merger rate and its evolution can vary by factors of 10, depending upon the method and assumptions used to count mergers. Using physical-motivated timescales from a large suite of galaxy merger simulations, I am able to reconcile the discrepancies between different measurements of the galaxy merger rate at z<1. The frequency of gas-rich mergers has increased strongly from z~0 to z~1, while the global galaxy merger rate evolved more modestly. Finally, I will discuss the prospects for identifying galaxy mergers at z~2 and beyond with the Cosmic Assembly Near-infrared Extragalactic Legacy Survey.

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17/01/12 (Tuesday)
12:30, D30 | ESO Garching
Lunch Talk
Talk — The radio sky at 12mm - latest science results from the AT20G survey
Elaine Sadler (University of Sydney)

Abstract

The Australia Telescope 20 GHz (AT20G) survey is a sensitive imaging survey of the entire southern sky (south of declination 0 degrees, at Galactic latitude |b|> 1.5 deg) carried out with the Australia Telescope Compact Array in the 12 millimetre band. The kinds of radio sources seen at 12mm are significantly different from those in seen in lower-frequency radio catalogues like NVSS and FIRST. I will discuss some recent science results from AT20G, including the discovery of a large population of young and recently-restarted radio galaxies. I will also mention some scientific links to the large optical/IR sky surveys currently underway at ESO, the Planck (CMB) and Fermi (gamma-ray) missions, and future work with ALMA.
10:00, D30 | ESO Garching
Star and Planet Formation Seminar
Talk — Star making at low-metallicity: the mass accretion process
Loredana Spezzi (ESO)

Abstract

The mass accretion rate (Macc) is a key parameter to constrain the models of both star and planet formation, for it affects both the disk structure and evolution as well as planet formation and migration. In particular, Macc studies in low-metallicity environments are particularly important because the probability of a star hosting a planet depends on stellar metallicity. We have conducted a multi-wavelength study of four star forming regions, spanning the age 1-14 Myrs, located between the 30 Doradus complex and the supernova SN1987A in the Large Magellanic Cloud (LMC), where the metallicity is much lower than in our Galaxy. We reliably identify about 1000 pre-main sequence (PMS) star candidates actively undergoing mass accretion and estimate their stellar properties and mass accretion rate (Macc). Our measurements represent the largest Macc dataset of low-metallicity stars presented so far. As such, they offer a unique opportunity to study on a statistical basis the mass accretion process in the LMC and, more in general, the evolution of the mass accretion process around low-metallicity stars. In this talk, I will review the main results of this study in comparison to similar study in the Milky Way and the Small Magellanic Cloud.
10/01/12 (Tuesday)
12:30, D29 | ESO Garching
Lunch Talk
Talk — Tales about Supernovae
Jason Spyromilio (ESO)

Abstract

A review of the scientific evolution in the field of supernovae over the past 25 years with an emphasis on work that underpins the use of supernovae as standard candles. Some recent results from the work following on from the original Lambda discovery papers will also be discussed.