Half-Light Radius Measurements of Andromeda Dwarf Satellites from the Isaac Newton Telescope Survey Using Exponential, Plummer, and S\'ersic Fits

TL;DR

This study measures the half-light radii of Andromeda's dwarf satellites using multi-epoch INT survey data, fitting various models to surface brightness profiles, and provides publicly available catalogs for future research.

Contribution

It introduces a new set of half-light radius measurements derived from multi-epoch imaging and compares them with literature, enhancing understanding of dwarf galaxy structures.

Findings

Half-light radii are consistent with literature values.

Subtle variations linked to stellar distribution and morphology.

Distances estimated via TRGB are consistent with previous results.

Abstract

We present half-light radius measurements for the dwarf satellites of Andromeda, based on multi-epoch imaging from the Isaac Newton Telescope (INT) Monitoring Survey of Local Group dwarf galaxies. This analysis is conducted within a larger study to identify long-period variable (LPV) stars in these galaxies. The survey was performed with the Wide Field Camera on the 2.5-m INT and covers multiple epochs obtained between 2015 and 2018 in the i (Sloan) and V (Harris) bands. To determine the half-light radii, we derived surface brightness and number density profiles for each system and fitted them with Exponential, Plummer, and S\'ersic models. The resulting half-light radii are in good agreement with literature values but reveal subtle variations linked to differences in stellar distribution and morphology. Distances were independently estimated using the Tip of the Red Giant Branch (TRGB) method, yielding values consistent with previous determinations. The complete photometric and variability catalogs will be made publicly available through CDS/VizieR, providing a valuable resource and foundation for future studies of the structure, stellar populations, and evolution of Andromeda's dwarf companions.