Abundance matching tested on small scales with galaxy dynamics

TL;DR

This study tests the abundance matching model's predictions against galaxy data from the Virgo cluster, finding good agreement in the relation's slope but more scatter than predicted, especially in massive galaxies.

Contribution

It provides an empirical validation of abundance matching predictions across a wide range of galaxy masses using detailed observational data.

Findings

AM reproduces the slope and normalization of the SHMR.

Observed scatter exceeds AM predictions by a factor of ~5.

AM overpredicts stellar masses in massive galaxies with M*>5x10^{10} M_sun.

Abstract

We present a comprehensive test of the relation between stellar and total mass in galaxies as predicted by popular models based on abundance matching (AM) techniques. We use the ``Spectroscopy and H-band Imaging of Virgo cluster galaxies'' (SHIVir) survey with photometric and dynamical profiles for 190 Virgo cluster galaxies to establish a relation between the stellar and dynamical masses measured within the isophotal radius $r_{23.5}$. Various dark matter and galaxy scaling relations are combined with results from the NIHAO suite of hydrodynamical simulations to recast AM predictions in terms of these observed quantities. Our results are quite insensitive to the exact choice of dark matter profile and halo response to baryon collapse. We find that theoretical models reproduce the slope and normalization of the observed stellar-to-halo mass relation (SHMR) over more than three orders of magnitude in stellar mass $(10^8 < M_*/M_{\odot} < 2 \times 10^{11})$. However, the scatter of the observed SHMR exceeds that of AM predictions by a factor $\sim$5. For systems with stellar masses exceeding $5 \times 10^{10}~M_{\odot}$, AM overpredicts the observed stellar masses for a given dynamical mass. The latter offset may support previous indications of a different stellar initial mass function in these massive galaxies. Overall our results support the validity of AM predictions on a wide dynamical range.