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 30 min prior  to the beginning of the talk.


October 2014

29.10.14 (Wednesday)
12:00
"Magnesium isotopes in the Milky Way Bulge and inner Disk"
Anders THYGESEN (Landessternwarte Heidelberg, Germany)
Abstract
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"Magnesium isotopes in the Milky Way Bulge and inner Disk"

Anders THYGESEN (Landessternwarte Heidelberg, Germany)

Abstract

The Milky Way Bulge is one of the most poorly understood components of our galaxy, with the formation history still being strongly debated (early collapse vs. disk instability). The study of the chemical composition of the Bulge stars as well as stars in the inner disk can yield additional constraints to this debate. All knowledge of the chemical history has so far been derived by the use of elemental abundances, but so far no studies of the isotopic mixture have been attempted. In particular, Mg isotopes in stars have the possibility of constraining the enrichment timescales for stellar populations, as the heavy isotopes (25Mg and 26Mg) can be efficiently produced in AGB stars, whereas the lightest and most abundant (24Mg) is mainly produced in type II supernovae. In this talk I will present initial results from a study of the magnesium isotopic mixture in this Milky Way component. We have analyzed 3 giants in the Milky Way Bulge, including 2 stars in the Bulge globular cluster NGC6522, and 7 giants in the inner disk, where we derive the isotopic mixture from the MgH A-X molecular bands. We use high resolution, high signal-to-noise VLT/UVES optical spectra. These results represent the first measurements of isotopic mixtures in this part of the Milky Way, and will yield new clues to the formation history of this poorly understood component of the Milky Way.

30.10.14 (Thursday)
12:00
"AGN torus and Starburst scenario in the central 100 pc of IC 3639"
Juan Antonio FERNANDEZ ONTIVEROS (Max-Planck-Institut für Radioastronomie, Bonn)
Abstract
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"AGN torus and Starburst scenario in the central 100 pc of IC 3639"

Juan Antonio FERNANDEZ ONTIVEROS (Max-Planck-Institut für Radioastronomie, Bonn)

Abstract

The detection of the active nucleus in IC 3639 using the no-track mode in VLTI/MIDI corresponds to one of the faintest measurements so far achieved with mid-IR interferometry. Strong star-formation and AGN activity coexist on small spatial scales in the nucleus of IC 3639, within the inner 100 pc. The resulting brightness distribution shows the contribution of the the AGN, which explains dust heating in the innermost parsecs, plus the star-formation component that heats the dust at larger scales and dominates the total mid-IR luminosity. The case of IC 3639 is in contrast with the quenching of star-formation activity by AGN feedback scenario.


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