The PAndAS View of the Andromeda Satellite System. III. Dwarf galaxy detection limits

TL;DR

This study assesses the detection capabilities of the PAndAS survey for dwarf galaxies, considering size, luminosity, and location, to better understand Andromeda's satellite system and dwarf galaxy formation.

Contribution

It provides detailed detection limits for dwarf galaxies in the PAndAS survey, accounting for spatial variations and contamination effects, which aids future satellite galaxy studies.

Findings

Detection limits depend on size, luminosity, and location.

Recovery fractions vary with contamination levels.

Effective surface brightness for 50% detection ranges from 28 to 30 mag/arcsec².

Abstract

We determine the detection limits of the search for dwarf galaxies in the Pan-Andromeda Archaeological Survey (PAndAS) using the algorithm developed by the PAndAS team. The recovery fractions of artificial dwarf galaxies are, as expected, a strong function of physical size and luminosity and, to a lesser extent, distance. We show that these recovery fractions vary strongly with location in the surveyed area because of varying levels of contamination from both the Milky Way foreground stars and the stellar halo of Andromeda. We therefore provide recovery fractions that are a function of size, luminosity, and location within the survey on a scale of 1 square degree. Overall, the effective surface brightness for a 50-percent detection rate range between 28 and 30 mag per square arcsecond. This is in line with expectations for a search that relies on photometric data that are as deep as the PAndAS survey. The derived detection limits are an essential ingredient on the path to constraining the global properties of Andromeda's system of satellite dwarf galaxies and, more broadly, to provide constraints on dwarf galaxy formation and evolution in a cosmological context.