Spitzer Photometry of ~1 Million Stars in M31 and 15 Other Galaxies

TL;DR

This paper provides extensive Spitzer IR point-source catalogs for M31 and 15 other nearby galaxies, enabling detailed studies of IR-bright stellar populations and aiding future JWST observations.

Contribution

It presents a large, uniformly processed catalog of over one million IR sources in multiple galaxies, expanding resources for extragalactic stellar population research.

Findings

Catalog contains ~1 million sources including ~859,000 in M31

Data enables improved understanding of IR-bright stellar populations

Supports planning for JWST observations

Abstract

We present Spitzer IRAC $3.6-8 \mu$m and MIPS $24 \mu$m point-source catalogs for M $31$ and $15$ other mostly large, star forming galaxies at distances $\sim3.5-14$ Mpc including M $51$, M $83$, M $101$ and NGC $6946$. These catalogs contain $\sim1$ million sources including $\sim859,000$ in M 31 and $\sim116,000$ in the other galaxies. They were created following the procedures described in Khan et al. (2015) through a combination of point spread function (PSF) fitting and aperture photometry. These data products constitute a resource to improve our understanding of the IR-bright ($3.6-24 \mu$m) point-source populations in crowded extragalactic stellar fields and to plan observations with the James Webb Space Telescope.