A Wide Field, Low Frequency Radio Image of the Field of M31: II. -- Source Classification and Discussion

Abstract

We have previously presented the results of a 325 MHz radio survey of M31, conducted with the A-configuration of the Very Large Array. In this survey, a total of 405 radio sources between <6" and 170" in extent were mapped with a resolution of 6" and a sensitivity of ~0.6 mJy/beam. Here, we compare the resultant source list and image with other radio, IR, optical, X-ray observations and catalogs of the region. Through this, we were able to identify five supernova remnant (SNR) candidates and three pulsar wind nebula (PWN) candidates in M31, as well as three Milky Way radio stars, a possible Milky Way Planetary Nebula, and a bevy of interesting extragalactic objects: a BL Lac, a Giant Radio Galaxy, a galaxy merger, and several high-z radio galaxy candidates. In addition, a large number of compact (<6") extremely steep spectrum sources ($α\leq -1.6; S_ν \propto ν^α$) were detected whose nature is unknown.