New Views in the Ultraviolet of the Andromeda Galaxy Enabled by the AstroSat/UVIT Telescope

The UVIT instrument on AstroSat has carried out a survey of our neighboring Andromeda galaxy, with a set of 19 fields to cover its large angular extent. The survey is complete in the FUV F148W filter, and about halfcomplete in FUV F169M, FUV F172M, NUV N219M and NUV N279N filters. The NUV coverage is incomplete due to failure of the NUV detector partway through the AstroSat mission. The survey and its scientific results are reviewed, with emphasis on the most recent results. From the Andromeda survey, catalogs of point sources in the FUV and NUV filters have been created. Young stars have been detected in the bulge. FUV and NUV counterparts of the X-ray sources in Andromeda were identified and are predominantly globular clusters. Clusters from the HST/Pan-Andromeda Hubble Treasury (PHAT), which covers a large part of the NE half of the galaxy, have been identified in UVIT FUV and NUV and characterized using their multi-band FUV to IR photometry. FUV variable stars have been identified in Andromeda observations with exposures separated by a few years, and cross-matched with hot stars. The Andromeda bulge has been characterized in FUV and NUV wavelengths for the first time, including measurement of structural parameters and modelling of the star formation and metallicity history of the bulge.

Automated summary

The UVIT instrument on AstroSat has conducted a survey of the Andromeda galaxy, providing important insights such as the detection of young stars in the bulge region, the identification of X-ray sources and their correlation with globular clusters, and the characterization of the Andromeda bulge in terms of its structural parameters and star formation history.