The Halo Mass Function of Late-type Galaxies from H I Kinematics
Abstract
We present an empirical method to measure the halo mass function (HMF) of galaxies. We determine the relation between the H I line width from single-dish observations and the dark matter halo mass (M 200) inferred from rotation-curve fits in the Spitzer Photometry and Accurate Rotation Curves (SPARC) database, then we apply this relation to galaxies from the H I Parkes All Sky Survey (HIPASS) to derive the HMF. This empirical HMF is well fit by a Schechter function, and matches that expected in the Λ Cold Dark Matter (ΛCDM) model over the range 1010.5 < M 200 < 1012 M ⊙. More massive halos must be poor in neutral gas to maintain consistency with the power law predicted by ΛCDM. We detect no discrepancy at low masses. The lowest halo mass probed by HIPASS, however, is just greater than the mass scale where the Local Group missing satellite problem sets in. The integrated mass density associated with the dark matter halos of H I-detected galaxies sums to Ωm,gal ≈ 0.03 over the probed mass range.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2019
- DOI:
- 10.3847/2041-8213/ab53e6
- arXiv:
- arXiv:1911.00517
- Bibcode:
- 2019ApJ...886L..11L
- Keywords:
-
- Galaxy dark matter halos;
- Galaxy masses;
- Galaxy kinematics;
- H I line emission;
- Galaxy abundances;
- Galaxy counts;
- Cold dark matter;
- Dark matter density;
- Stellar mass functions;
- Galaxy rotation curves;
- Galaxy formation;
- Galaxy evolution;
- 1880;
- 607;
- 602;
- 690;
- 574;
- 588;
- 265;
- 354;
- 1612;
- 619;
- 595;
- 594;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 7 pages, 3 figures, 1 table. Accepted for publication in ApJ Letters