The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs
Wechsler, Risa H.
Tollerud, Erik J.
Marshall, Phil J.
AffiliationUniv Arizona, Dept Astron
galaxies: luminosity function, mass function
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationThe SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs 2017, 847 (1):4 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe present the survey strategy and early results of the "Satellites Around Galactic Analogs" (SAGA) Survey. The SAGA. Survey's goal is to measure the distribution of satellite galaxies around 100 systems analogous to the Milky Way down to the luminosity of the Leo I dwarf galaxy (M-r < -12.3). We define a Milky Way analog based on K-band luminosity and local environment. Here, we present satellite luminosity functions for eight Milky-Way-analog galaxies between 20 and 40. Mpc. These systems have nearly complete spectroscopic coverage of candidate satellites within the projected host virial radius down to r(o) < 20.75 using low-redshift gri color criteria. We have discovered a total of 25 new satellite galaxies: 14. new satellite galaxies meet our formal criteria around our complete host systems, plus 11 additional satellites in either incompletely surveyed hosts or below our formal magnitude limit. Combined with 13 previously known satellites, there are a total of 27 satellites around 8 complete Milky-Way-analog hosts. We find a wide distribution in the number of satellites per host, from 1 to 9, in the luminosity range for which there are 5 Milky Way satellites. Standard abundance matching extrapolated from higher luminosities predicts less scatter between hosts and a steeper luminosity function slope than observed. We find that the majority of satellites (26 of 27) are star-forming. These early results indicate that the Milky Way has a different satellite population than typical in our sample, potentially changing the physical interpretation of measurements based only on the Milky Way's satellite galaxies.
VersionFinal published version
SponsorsNSF [AST-1517148]; John S. Guggenheim Foundation; Samuel P. Langley PITT PACC Postdoctoral Fellowship; Weiland Family Stanford Graduate Fellowship; Giacconi Fellowship; NASA through Hubble Fellowship - Space Telescope Science Institute [51316.01]; NASA [NAS 5-26555]; STFC (UK); ARC (Australia); AAO
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