A Wide-Field, Low-Frequency Radio Survey of the Field of M31. I. Construction and Statistical Analysis of the Source Catalog

We present here the results of a 325 MHz radio survey of M31, conducted with the A configuration of the Very Large Array. The survey covered an area of 7.6 deg2, and a total of 405 radio sources between ≲6'' and 170'' in extent were mapped with a resolution of 6'' and a 1 σ sensitivity of ~0.6 mJy beam-1. For each source, its morphological class, major axis θM, minor axis θm, position angle θPA, peak flux I, integrated flux density S, spectral index α, and spectral curvature parameter φ were calculated. A comparison of the flux and radial distribution—both in the plane of the sky and in the plane of M31—of these sources with those of the XMM-Newton Large-Scale Structure Survey and Westerbork Northern Sky Survey revealed that a vast majority of sources detected are background radio galaxies. As a result of this analysis, we expect that only a few sources are intrinsic to M31. These sources are identified and discussed in an accompanying paper.