Author ORCID Identifier

Stacy S. McGaugh

Document Type

Article

Publication Date

11-15-2019

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 o˙. 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.

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

Language

English

Publication Title

Astrophysical Journal Letters

Grant

1911909

Rights

© 2019. The American Astronomical Society. All rights reserved. This content is free to access, download, and share. For all other uses, you must obtain permission to reuse content: https://journals.aas.org/article-charges-and-copyright/#AAS_material

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