Light-ish Elements in Dwarf Galaxies: The Enigmas of Lithium, Carbon, Magnesium, and More

报告人: Prof. Evan Kirby (Caltech)

报告时间: 2016年4月07日 14:00

报告地点: South 727, Mong Man-wei Science Technology Building (蒙民伟科技南楼S727)

Abstract: Dwarf galaxies in the Local Group are good testing grounds for chemical evolution models.  First, they are simple, usually short-lived systems.  Second, they are near enough for resolved stellar spectroscopy.  Multi-object spectrographs, like Keck/DEIMOS, have allowed the chemical characterization of thousands of stars in dwarf galaxies.  The lighter elements like lithium and carbon, are windows into stellar evolution.  The heavier alpha elements, like magnesium and calcium, trace galactic evolution.  I will show DEIMOS measurements of several elements in eight dwarf galaxies.  The results will illuminate some mysteries about unexplained mixing processes on the red giant branch as well as the broader chemical evolution of the galaxies over hundreds of millions of years.

Bio: Evan Kirby is an assistant professor of astronomy at the California Institute of Technology (Caltech).  He earned a BA in physics from Stanford University in 2004 and a PhD from the University of California Santa Cruz in 2009.  He was a Hubble Fellow at Caltech from 2009 to 2012 and a Center for Galaxy Evolution Fellow at the University of California Irvine from 2012 to 2014.  His research focuses on how the elements of the periodic table originated and evolved in our galaxy and others.  He also specializes in the study of very small galaxies and how they relate to dark matter and the creation of the elements.