Galaxy Groups Within 3500 km s-1
Abstract
A study of the group properties of galaxies in our immediate neighborhood provides a singular opportunity to observationally constrain the halo mass function, a fundamental characterization of galaxy formation. Detailed studies of individual groups have provided the coefficients of scaling relations between a proxy for the virial radius, velocity dispersion, and mass that usefully allow groups to be defined over the range {10}10{--}{10}15 M ⊙. At a second hierarchical level, associations are defined as regions around collapsed halos extending to the zero-velocity surface at the decoupling from cosmic expansion. The most remarkable result of the study emerges from the construction of the halo mass function from the sample. At ∼1012 M ⊙, there is a jog from the expectation Sheth-Tormen function, such that halo counts drop by a factor ∼3 in all lower mass bins.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2017
- DOI:
- 10.3847/1538-4357/aa76db
- arXiv:
- arXiv:1705.08068
- Bibcode:
- 2017ApJ...843...16K
- Keywords:
-
- dark matter;
- galaxies: groups: general;
- galaxies: luminosity function;
- mass function;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 34 pages, 17 figures and 4 tables. Accepted for publication in The Astrophysical Journal