The spatial distribution of satellite galaxies within halos: Measuring the very small scale angular clustering of SDSS galaxies

Journal Article · Wed Jun 10 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/806/1/125· OSTI ID:22883055

Piscionere, Jennifer A.; Berlind, Andreas A. ^[1]; McBride, Cameron K. ^[2]; Scoccimarro, Román ^[3]

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1. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)
2. Center for Astrophysics, Harvard University, Cambridge, MA 02138 (United States)
3. Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10003 (United States)

We measure the angular clustering of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 in order to probe the spatial distribution of satellite galaxies within their dark matter halos. Specifically, we measure the angular correlation function on very small scales (7″–320″) in a range of luminosity threshold samples (absolute r-band magnitudes from −18 up to −21) that are constructed from the subset of SDSS that has been spectroscopically observed more than once (the so-called plate overlap region). We choose to measure angular clustering in this reduced survey footprint in order to minimize the effects of fiber collision incompleteness, which are otherwise substantial on these small scales, and we discuss the possible impact that fiber collisions have on our measurements. We model our clustering measurements using a fully numerical halo model that populates dark matter halos in N-body simulations to create realistic mock galaxy catalogs. The model has free parameters that specify both the number and spatial distribution of galaxies within their host halos. We adopt a flexible density profile for the spatial distribution of satellite galaxies that is similar to the dark matter Navarro–Frenk–White (NFW) profile, except that the inner slope is allowed to vary. We find that the angular clustering of our most luminous samples (M{sub r} < −20 and −21) suggests that luminous satellite galaxies have substantially steeper inner density profiles than NFW. Lower-luminosity samples are less constraining, however, and are consistent with satellite galaxies having shallow density profiles. Our results confirm the findings of Watson et al. while using different clustering measurements and modeling methodology.

• OSTI ID: 22883055
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 806; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANGULAR CORRELATION
CATALOGS
COLLISIONS
COMPUTERIZED SIMULATION
CORRELATION FUNCTIONS
DENSITY
GALAXIES
LUMINOSITY
SPATIAL DISTRIBUTION
UNIVERSE