December 2018

17/12/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — Adaptive Optics for Astronomy
Sylvain Oberti (ESO)

Abstract

In this talk, I will introduce the motivations of adaptive optics for astronomy, the basic atmospheric physics and technical principle. Then, we will focus on the limitations of adaptive optics and possible remedies. Finally, I will briefly present the main adaptive optics modes offered at the VLT and in the future at the ELT, and their relevance for science. Real observation examples will be provided as illustration.

November 2018

05/11/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — The shell, multiplexing, version control and other command line goodness
Mathias André (ESO)
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Abstract

In this talk, we'll first have a look at how to make better use of the shell by looking at some of the most useful commands and how to combine them.

In the second part we'll look at a few other tools that can be useful if you have to write, maintain or run any kind of code: git, tmux and docker. ***Bring your laptop!***

October 2018

22/10/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — Things that go "dip" in the night: from disintegrating planets to alien megastructures
Megan Ansdell (University of California Berkeley, Department of Astronomy)

Abstract

The advent of space-based telescopes that provide high-precision time-series photometry, such as CoRoT and Kepler, have revealed a zoo of stellar variability on timescales from minutes to months. In this talk, I will focus on classes of objects whose light curves show distinctive "dips" that can tell us a surprising amount about planet formation, evolution, and death. These include disintegrating planets, young dipper systems, likely exocomets, and unlikely alien megastructures.

08/10/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — History of radio galaxies
Guillaume Drouart (Curtin Universtity of Technology)
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Abstract

Radio galaxies - aka type 2 radio loud AGN - have been instrumental in our understanding of galaxy evolution. I will present a short review on the history of radio galaxies from the 60s to nowadays and some of the key discoveries made thanks to these particular objects. From an observational perspective, I will cover the main physical properties associated with galaxy hosts and supermassive black holes, jets and lobes and what kind of information radio observations can give us in comparison to other AGN classes. I will also remember some of the questions that are still debated, with sometimes contradictory results. Finally, I will give a short prospective in the near future, and how a second "golden age" of radio-astronomy will soon be upon us!

September 2018

24/09/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — Cosmology with Supernovae
Bruno Leibundgut (ESO)
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Abstract

The basic cosmological model for the interpretation of supernova data will be presented. Several fundamental tests of the cosmological model based on supernova observations will be described. The latest determinations of the cosmological parameters will be discussed.

10/09/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — Astrophotos: From papers to public’s eyes
Mahdi Zamani (ESO)
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Abstract

In a time when cutting-edge observatories are publicly funded, the need for more communications with general public and sharing scientific results in a visually pleasant way is on the rise. The talk will be a quick surf on deep waters of scientific image processing  for outreach purpose at ESO and Hubble/ESA. That includes exploring the art used in the today's image processing methods with respect of  scientific boundaries and Astronomical Visualization Metadata (AVM) potentials for public and scientific community.

June 2018

18/06/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Talk — Learning the (other) worlds 2.0
Valentin Ivanov (ESO)
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Abstract

I will review the history of the exoplanet research, the latest results, and will summarize the most important questions that have remained unanswered.

04/06/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Paola Andreani (ESO)

Abstract

Physicists believe they have made a huge progress in the concept of time since they have imported its ‘meaning’ into physics from the philosophers in the XVII century.

We understand time dilation in special and general relativity but still we have advanced enough in the notion of time-flow and the meaning of ‘present’.

I will introduce the nowadays hot debate among theoretical physicists according to which time has either disappeared from the equations, like in quantum gravity, or has become ‘fundamental and real’ and we need to re-write the physical laws.

In this last case: what if the the laws of physics were not timeless? What if they could evolve?

May 2018

07/05/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Jason Spyromilio (ESO)

Abstract

The continuation of an incoherent discussion of emission by atoms and molecules in astrophysical plasmas. A quick recap of forbidden lines will be followed by a discussion diatomic molecules and recombination processes.

April 2018

23/04/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Paolo Padovani (ESO)

Abstract

IceCube has recently reported the discovery of high-energy neutrinos of astrophysical origin, opening up the PeV (10^15 eV) sky. These observations are challenging to interpret on the astronomical side and have triggered a fruitful collaboration across particle and astro-physics. I will first discuss neutrinos in an astronomical context. I will then make the case for extreme blazars, i.e. strong, very high energy gamma-ray sources of the high energy peaked type, to be the counterparts of at least some of the IceCube neutrinos. This scenario is supported by positional and energetic matches, theoretical modelling, and Monte Carlo simulations and has been confirmed very recently by the detection of gamma-ray emission from an extreme blazar within the error circle of an IceCube event. The talk is self-contained, requires no previous knowledge of neutrinos or blazars, and has been prepared for a very broad audience.

09/04/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Torsten Ensslin & Philipp Arras (MPA & Heidelberg University)

Abstract

Information field theory (IFT) provides probabilistic image reconstruction algorithms for incomplete and noisy data. Numerical information field theory (NIFTy) is a Python library for IFT algorithms. We provide a short introduction into the usage of NIFTy for astronomical data with a practice oriented demo, covering the Wiener filter and radio interferometric imaging. NIFTy is maintained by the IFT group at the MPI for Astrophysics and is available here: https://gitlab.mpcdf.mpg.de/ift/NIFTy

March 2018

12/03/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Adriano Agnello (ESO)

Abstract

Gravitational lensing allows us to weigh distant objects, measure cosmological distances, and get a super-resolved view of very distant sources. Its various regimes (strong lensing, weak lensing, microlensing and variations on these themes) have manifold applications in contemporary astrophysics.

In this mini-lecture, I will start with an overview of the basic principles and formalism, and some quick numbers for different astrophysical regimes. The second part of this mini-lecture will present a birdseye view of applications, somewhat biased towards topics that I have worked upon.

I will keep the formalism to a minimum. Links to more exhaustive materials will be provided with the slides.

05/03/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Jacek Krelowski (Torun Center for Astronomy, Nicolaus Copernicus University)
View slides |

Abstract

Interstellar clouds, filling the space between stars, may be revealed thanks to either some spectral features originating in very rarefied gas or to the selective attenuation of the starlight, known as interstellar extinction. Selectivity means that a star, shining through a cloud or clouds is more red than intrinsically as the extinction is higher in blue range than in red. This is why extinction is nicknamed "reddening".

Extinction is being carried by dust particles of the submicron size. They are believed to be originated in vicinities of mass-loosing stars and then - to evolve in the interstellar space from bare to core-mantle ones.

However, grains, seen in any individual cloud, may be apparently seriously of different size, shape and chemical/cristalline composition. In a vast majority of cases one observes distant stars through several clouds, seeing thus an ill-defined average(s) which are very difficult to be interpreted in terms of any physical theory.

Currently I try, together with Ralf Siebenmorgen and Jonathan Smoker, to retrieve and compare extinction laws in several individual interstellar clouds.

February 2018

26/02/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Martin Zwaan (ESO)
12/02/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Fabrizio Arrigoni Battaia (ESO)
View slides |

Abstract

The hydrogen Lyman-alpha line is extremely important in many fields of astrophysics. In particular, this UV line is conveniently redshifted to the visible and near infrared wavelength ranges for high-redshift objects, making it observable from the ground. The hydrogen Lyman-alpha thus provides the main observational window on the formation and evolution of high redshift galaxies. However, this resonant line undergoes complex radiation transfer effects, which need careful modelling in order to extract information on the kinematics and geometry of the gas. This information is thus enclosed in the line shape. In this lesson I will briefly introduce the emission mechanisms for this line and explain the resonant scattering process.

January 2018

29/01/18 (Monday)
10:45, Library (ESO HQ, Garching) | ESO Garching
KES: Knowledge Exchange Series
Celine Peroux (ESO)
View slides |

Abstract

The baryon cycle refers to the complex physical processes by which gas travels into, through, and out of galaxies. In this lecture, I will first review simulation and observational results which, together, have provided important fresh clues on the physics of galactic gas flows. I will then discuss prospects of detecting the circumgalactic medium in emission and other future progress which will likely impact galaxy formation studies at all cosmic epochs.