Statistics of Satellite Galaxies around Milky Way-Like Hosts
We calculate the probability that a Milky-Way (MW)-like halo in the standard cosmological model has the observed number of Magellanic Clouds (MCs). The statistics of the number of MCs in the lambda cold dark matter model are in good agreement with observations of a large sample of Sloan Digital Sky Survey (SDSS) galaxies. Under the subhalo abundance matching assumption of a relationship with small scatter between galaxy r-band luminosities and halo internal velocities v{sub max}, we make detailed comparisons to similar measurements using SDSS Data Release 7 data by Liu et al. Models and observational data give very similar probabilities for having zero, one, and two MC-like satellites. In both cases, MW luminosity hosts have just an {approx}10% chance of hosting two satellites similar to the MCs. In addition, we present a prediction for the probability for a host galaxy to have N{sub sats} satellite galaxies as a function of the magnitudes of both the host and satellite. This probability and its scaling with host properties is significantly different from that of mass-selected objects because of scatter in the mass-luminosity relation and because of variations in the star formation efficiency with halo mass.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1032748
- Report Number(s):
- SLAC-PUB-14613; ASJOAB; arXiv:1011.6373; TRN: US201202%%320
- Journal Information:
- Astrophysical Journal, Vol. 743, Issue 2; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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