Measuring the halo mass function in loose groups

TL;DR

This study compares the HI mass function and velocity distribution in six galaxy groups similar to the Local Group, confirming the presence of the missing satellite problem beyond our Local Group.

Contribution

It provides the first comparative analysis of HI mass functions in multiple loose galaxy groups, extending the missing satellite problem to these environments.

Findings

HI mass functions are consistent across groups and the Local Group

The missing satellite problem is confirmed in other galaxy groups

Velocity distribution functions are similar across studied groups

Abstract

Using data from our Parkes & ATCA HI survey of six groups analogous to the Local Group, we find that the HI mass function and velocity distribution function for loose groups are the same as those for the Local Group. Both mass functions confirm that the "missing satellite" problem exists in other galaxy groups.