The Connection between Galaxies and Dark Matter Structures in the Local Universe

Journal Article · Wed Jul 11 04:00:00 EDT 2012 · Submitted to Astrophysical Journal

OSTI ID:1045808

Reddick, Rachel M; Wechsler, Risa H; Tinker, Jeremy L; Behroozi, Peter S

We provide new constraints on the connection between galaxies in the local Universe, identified by the Sloan Digital Sky Survey (SDSS), and dark matter halos and their constituent substructures in the {Lambda}CDM model using WMAP7 cosmological parameters. Predictions for the abundance and clustering properties of dark matter halos, and the relationship between dark matter hosts and substructures, are based on a high-resolution cosmological simulation, the Bolshoi simulation. We associate galaxies with dark matter halos and subhalos using subhalo abundance matching, and perform a comprehensive analysis which investigates the underlying assumptions of this technique including (a) which halo property is most closely associated with galaxy stellar masses and luminosities, (b) how much scatter is in this relationship, and (c) how much subhalos can be stripped before their galaxies are destroyed. The models are jointly constrained by new measurements of the projected two-point galaxy clustering and the observed conditional stellar mass function of galaxies in groups. We find that an abundance matching model that associates galaxies with the peak circular velocity of their halos is in good agreement with the data, when scatter of 0.20 {+-} 0.03 dex in stellar mass at a given peak velocity is included. This confirms the theoretical expectation that the stellar mass of galaxies is tightly correlated with the potential wells of their dark matter halos before they are impacted by larger structures. The data put tight constraints on the satellite fraction of galaxies as a function of galaxy stellar mass and on the scatter between halo and galaxy properties, and rule out several alternative abundance matching models that have been considered. This will yield important constraints for galaxy formation models, and also provides encouraging indications that the galaxy - halo connection can be modeled with sufficient fidelity for future precision studies of the dark Universe.

• Research Organization: SLAC National Accelerator Laboratory (SLAC)
• Sponsoring Organization: US DOE Office of Science (DOE SC); National Science Foundation (NSF)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1045808
• Report Number(s): SLAC-PUB-15183; arXiv:1207.2160
• Journal Information: Submitted to Astrophysical Journal, Journal Name: Submitted to Astrophysical Journal
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ACCURACY
Astrophysics
ASTRO
GRQC
GALAXIES
NONLUMINOUS MATTER
SATELLITES
SIMULATION
SKY
UNIVERSE
VELOCITY