Seminar series

What is a Galaxy?

Beth Willman, Haverford college

23 Feb 2012 - 16:00


In the past five years more than a dozen tiny, dwarf galaxies have been discovered around the Milky Way. Many of these discoveries are 100 times less luminous than any galaxy previously kown and a million times less luminous than the Milky Way itself. These objects have made astronomers question the very meaning of the word "galaxy". The advent of wide field, digital sky surveys (in particular the Sloan Digital Sky Survey) facilitated these discoveries, and hint that "ultra-faint" galaxies like the recent discoveries might actually be the most numerous type of galaxies in the Universe. 
This talk will highlight:
i. how we can see galaxies that are effectively invisible in images on the sky, 
ii. the brewing controversy on the definition of the term "galaxy", and 
iii. new photometric and spectroscopic studies of and searches for ultra-faint Milky Way satellites.

LCO Seminar Series,
6740 Cortona Dr, Suite 102,