Astrophysically Motivated Bulge Disk Decompositions in SDSS

Claire Lackner (Princeton University)
Friday, November 4, 2011 - 9:15am

The division of galaxies into disk and spheroid components is very old and reasonably successful. I will discuss a new set of two-dimensional bulge-disk(B+D) decompositions for 70,000 nearby Sloan Digital Sky Survey (SDSS) galaxies, the largest such set to date.  Each galaxy is fit with five different 2-dimensional models and the best fitting model is selected based on chi-squared values and astrophysical constraints (color, bulge-to-total ratio, shape, etc.). Fifty percent of the galaxies cannot be fit with a B+D model, but this represents only 20% of the stellar mass in our sample. Bulge color and shape can be used to separate elliptical-like classical bulges from disk-like pseudo-bulges and this method agrees reasonably well with other methods used to distinguish classical bulges from pseudo bulges. This large data set can be used to study the properties of different morphological types over a large range of galaxy properties and environments.

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