Confronting Cold Dark Matter Predictions with Observed Galaxy Rotations

Abstract

The rich statistics of galaxy rotations as captured by the velocity function (VF) provides invaluable constraints on galactic baryon physics and the nature of dark matter (DM). However, the comparison of observed galaxy rotations against cosmological models is prone to subtle caveats that can easily lead to misinterpretations. Our analysis reveals full statistical consistency between ~5000 galaxy rotations, observed in line-of-sight projection, and predictions based on the standard cosmological model (LCDM) at the mass-resolution of the Millennium simulation (HI line-based circular velocities above ~50 km/s). Explicitly, the HI linewidths in the HI Parkes All Sky Survey (HIPASS) are found consistent with those in S3-SAX, a post-processed semi-analytic model for the Millennium simulation. Previously found anomalies in the VF can be plausibly attributed to (1) the mass-limit of the Millennium simulation, (2) confused sources in HIPASS, (3) inaccurate inclination measurements for optically faint sources, and (4) the non-detectability of gas-poor early-type galaxies. These issues can be bypassed by comparing observations and models using linewidth source counts rather than VFs. We investigate if and how well such source counts can constrain the temperature of DM.

11 pages, 10 figures

References in corpus (9)

• The hierarchical formation of the brightest cluster galaxies
• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• Carnegie Hubble Program: A Mid-Infrared Calibration of the Hubble Constant
• Galaxy formation in WMAP1 and WMAP7 cosmologies
• The velocity function in the local environment from LCDM and LWDM constrained simulations
• The Northern HIPASS catalogue - Data presentation, completeness and reliability measures
• A direct measurement of the baryonic mass function of galaxies & implications for the galactic baryon fraction
• Understanding the H2/HI Ratio in Galaxies
• A Robust Measure of Cosmic Structure beyond the Power-Spectrum: Cosmic Filaments and the Temperature of Dark Matter

Cited by in corpus (21)

• Is there a "too big to fail" problem in the field?
• Fundamental Mass-Spin-Morphology Relation of Spiral Galaxies
• Detection of HI in distant galaxies using spectral stacking
• Atomic and molecular gas in IllustrisTNG galaxies at low redshift
• Warm dark matter does not do better than cold dark matter in solving small-scale inconsistencies
• Cosmological performance of SKA HI galaxy surveys
• An assessment of the "too big to fail" problem for field dwarf galaxies in view of baryonic feedback effects
• How to Reconcile the Observed Velocity Function of Galaxies with Theory
• Evidence for HI replenishment in massive galaxies through gas accretion from the cosmic web
• Hints against the cold and collisionless nature of dark matter from the galaxy velocity function
• The HI Velocity Function: a test of cosmology or baryon physics?
• Signatures of Dark Matter Halo Expansion in Galaxy Populations
• Giant disk galaxies : Where environment trumps mass in galaxy evolution
• The galaxy HI-(sub)halo connection and the HI spatial clustering of local galaxies
• Extended Tully-Fisher Relations using HI Stacking
• Precise Tully-Fisher Relations without Galaxy Inclinations
• Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers
• The Califa and Hipass velocity function for all morphological galaxy types
• The low mass end of the neutral gas mass and velocity width functions of galaxies in $\Lambda$CDM
• The circular velocity and halo mass functions of galaxies in the nearby Universe
• The north-south asymmetry of the ALFALFA HI velocity width function