NOAO >   Observing Info >   Approved Programs >   2014A-0325

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Proposal Information for 2014A-0325


PI: Marla Geha, Yale University, marla.geha@yale.edu
Address: Astronomy Department, New Haven, CT 06520, USA

CoI: Risa Wechsler, Stanford University
CoI: Phil Marshall, Stanford University
CoI: Ricardo Munoz, Universidad de Chile
CoI: Emily Sandford, Yale University
CoI: Erik Tollerud, Yale University
CoI: Ben Weiner, University of Arizona

Title: Searching for Dwarf Galaxy Satellites Around Milky Way Analogs

Abstract: The Milky Way (MW) galaxy is host to two dozen dwarf galaxy satellites. The brightest of these satellites and their properties do not fully agree with predictions from galaxy formation models. While it is possible that model predictions are incorrect, it is equally plausible that the MW's satellite population is not representative of a typical MW-mass galaxy. Here, we propose multi-object spectroscopy around two nearby (D < 30 Mpc) MW analog systems down to M_r=-12 (r=20.5). Spectroscopy is necessary because satellite galaxies are extremely difficult to distinguish from the thousands of higher redshift background galaxies via photometry alone. We impose color cuts to improve the efficiency of finding low redshift satellites, however, there remain over 2500 candidate satellites around each analog system. We will search for satellites out to the physical virial radius, 300 kpc, equivalent to 1 degree at these distances. The AAT's AAOmega 2dF is by far the most efficient instrument for this work. We request 3 nights with AAOmega to search for satellites around 2 MW analogs. The proposed observations will be the first complete satellite luminosity functions of any MW analog down to M_r < -12.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2014A-0325

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