Astrophysics Seminar: Mindy Townsend, Kansas University


Location: 184 Nieuwland Science Hall (View on map )

The satellite population around luminous red galaxies in the 25 square degree DESI Legacy Imaging Surveys Early Data Release

Mindy Townsend
Graduate Student
University of Kansas

Luminous Red Galaxies, or LRGs, were originally selected in the Sloan Digital Sky Survey as good tracers of large scale structure. Subsequent investigations showed them to be among the most massive galaxies in the Universe and dominated by uniformly old stellar populations. Despite being dominated by old stars, however, they have grown in stellar mass since z=1, implying that they grow predominantly via accretion of satellites. This picture has not yet been tested because of the lack of deep imaging data sets that both covers a large enough area of the sky to contain substantial numbers of LRGs and also is deep enough to detect faint satellites. We present our initial characterization of the satellite galaxy population of LRGs out to z=0.65. To accomplish this we use the 25 square degree Early Data Release (EDR) of the DESI Legacy Imaging Surveys, which are comprised of grz imaging to 2-2.5 mag deeper than SDSS, over a larger footprint, and with better image quality. Specifically, we present our first measurement of the number of satellite galaxies around LRGs. In addition, we forward model the distribution of the number of satellite galaxies that surround LRGs.

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