(1) Polarized Line Formation theories: the relevance of partial; (2) TBD; (3) On all things transit.

Fecha y hora
26 Mayo 2009 - 00:00 Europe/London


Idioma de la charla
Idioma de la presentación

1) Polarized Line Formation theories: the relevance of partial non-coherence in light scattering. Dr. Sampoorna Malali The basic theoretical tool for diagnosing the solar polarized line observations is the polarized radiative transfer equation including different physical mechanisms like Zeeman and Hanle effects. In this talk I present a short summary of the work carried out on the effects of random magnetic fields with finite correlation length on Zeeman line polarization (which forms first part of my thesis). Strong scattering lines like Ca I 4227 angstrom can only be properly modeled when partial non-coherence or partial frequency redistribution (PRD) is taken into account. PRD describes the angle-frequency correlation in a scattering event. I present a short summary of the work carried out on the theory of polarized line scattering in the arbitrary strength magnetic fields and including PRD (which forms second part of my thesis). (2) Stellar populations in dwarf elliptical galaxies. Dr. Mina Koleva Studying stellar populations in galaxies is a powerful tool to understand their formation and evolution. More, combining our knowledge about the individual galaxies we can reveal the cosmic evolution as a whole. My work until now consisted in developing a tool for studying stellar populations by comparing integrated light spectra to stellar population models. I tested extensively the latter, and found that the modern models agree. I applied my method to sixteen dwarf galaxies in the Fornax cluster and concluded that the bulk of their stars were already there at z=1. At the IAC, I intend to continue my work on models of stellar population, participate to instrumental developing, as well as study other types of galaxies in order to understand better the possible link between them. (3) On all things transit. Dr. Brandon Tingley Transit searches are now a well-established technique for discovering exoplanets. However, many aspects of the process are still being explored and refined. My work over the past several years has contributed to these efforts: discussing the use of transit color changes to identify eclipsing binaries in transit candidate lists, identifying transit candidates in poor sampled data for the Gaia mission, developing techniques to eliminate transit candidates without additional observations, and creating a new code to analyze the many detached eclipsing binaries found (and often neglected) during transit searches. In this talk, I will briefly discuss all of these topics.