Seminars and Colloquia at ESO/Santiago

For ESO and ESO-related Conferences and Workshops in Europe and Chile please check the main Conferences and Workshops page.


Broadcast of the ESO talks is available upon request.  If anyone is interested, kindly contact us via email
at least 60 min prior  to the beginning of the talk.


August 2015

27.08.15 (Thursday)
12:00
"The HARPS search for Neptunes around metal-poor stars"
Annelies MORTIER (University of St Andrews)
Abstract
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"The HARPS search for Neptunes around metal-poor stars"

Annelies MORTIER (University of St Andrews)

Abstract

Soon after the first exoplanets were detected it became clear that the frequency of orbiting giant planets is higher for metal-rich stars. The same clear trend has not been found for lower mass planets. An extensive observational program has been set up to use HARPS in order to detect lower mass planets around metal-poor stars. In this talk I will discuss the results as of yet for this program.


September 2015

4.09.15 (Friday)
12:00
"Resolving stellar populations with MUSE"
Tim-Oliver HUSSER (Universität Göttingen)
Abstract
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"Resolving stellar populations with MUSE"

Tim-Oliver HUSSER (Universität Göttingen)

Abstract

In my talk I will present the first results from a large observing campaign focused on the stellar populations in globular clusters using the recently commissioned integral field spectrograph MUSE. We are going to target about 30 clusters in the Milky Way, of which some have already been observed during commisioning and in GTO time. Using the technique of crowded field spectroscopy that we developed, we can resolve several thousand stellar spectra in a single datacube of the highly crowded cluster centres - as an example, about 90 minutes of observations on NGC 6397 yielded ~24,000 spectra of >12,000 stars, with a large fraction well below the main-sequence turnoff. Dedicated analysis tools allow us to determine radial velocities and stellar parameters for most stars in this sample. This will help us to better understand kinematics in globular clusters as well as their chemical compositions. In addition, multi-epoch observations will provide us for the first time with constraints on the distribution of binary periods inside the clusters.

11.09.15 (Friday)
12:00
"The HI and H2 content and sub-mm emission of galaxies over cosmic time: a semi-analytic and semi-empirical approach"
Gergely POPPING (ESO, Garching)
Abstract
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"The HI and H2 content and sub-mm emission of galaxies over cosmic time: a semi-analytic and semi-empirical approach"

Gergely POPPING (ESO, Garching)

Abstract

The star-formation activity of our Universe increased from early epochs (z~6), peaked around z=2, and then decreased by an order of magnitude until present age. To fully appreciate the physical origin of the star-formation activity of our Universe we need to focus on the gas content of galaxies over cosmic time. The most recent versions of cosmological models of galaxy formation explicitly include the detailed tracking of the atomic and molecular hydrogen content of galaxies and make predictions for the sub-mm lines emission from species such as CO, HCN, [CII]. New semi-empirical approaches provide data-driven predictions for the atomic and molecular gas content of galaxies. I will discuss the predictions made by these different types of models for the HI and H2 content of galaxies and their sub-mm line emission. These predictions include a weak evolution in the HI content and HI mass function of galaxies, strong evolution in the H2 content of galaxies, the weak evolution in the cosmic density of HI, the evolution of atomic and molecular gas in dark matter haloes, CO SLEDs of galaxies over cosmic time, and predictions for CO luminosity functions. I will compare these predictions to current observational samples, discuss future observing strategies, and will also demonstrate how the combination of cosmological and semi- empirical models can help to reveal caveats in our understanding of galaxy formation.

23.09.15 (Wednesday)
15:30
"Investigating the Distribution of volatiles in the Early Solar System"
Karen MEECH (Institute for Astronomy, University of Hawai’i)
Abstract
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"Investigating the Distribution of volatiles in the Early Solar System"

Karen MEECH (Institute for Astronomy, University of Hawai’i)

Abstract

The old view of comet formation suggests that the long-period (LP) comets are ice-rich planetesimals that formed in the vicinity of the giant planets and were scattered out to the Oort cloud as their orbits were perturbed by the giant planets. Later, orbital perturbations by passing stars injected them into the inner solar system where their ices began to sublime under the effect of solar radiation. Our paradigm of planet formation is changing with models that demonstrate that the giant planets migrated in the solar system, redistributing planetesimals – both bringing icy material to the inner solar system, and ejecting inner solar system material outward. As a consequence, it has become harder to chemically classify comets based on their region of origin to build up a picture of the early solar system volatile distribution. While we believe we have observations of most of the outer solar system small primitive bodies, we have never had samples of primitive building blocks of material from the Earth-feeding zone. Recent PanSTARRS 1 discoveries of objects on long-period comet orbits that are minimally active while at small perihelia have suggested the intriguing possibility that these could potentially represent inner solar system material that was ejected into the outer solar system during planet migration, that is now making its way back in. The first object discovered in 2013 turned out to have a spectrum redder than D-type objects, but exhibited low-level activity throughout perihelion passage. The second one, appears to have an S-type asteroid spectrum, and was likewise active at low level. Neither spectral type has been seen to be active before. A total of 90 objects have now been identified, a couple dozen or the original set are still observable. This talk will present these observations in the context of understanding volatile distribution in the early solar system, and its relation to delivery of water on Earth.


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