The FIRST Unbiased Survey for Radio Stars

Abstract

Comparison of the VLA FIRST survey with various catalogs of bright stars allows an examination of the prevalence of stellar radio emission independent of optical selection criteria. This FIRST unbiased survey for radio stars covers nearly 5000 deg 2 of the northern sky to a flux density limit of 0.7 mJy at 20 cm. Using astrometric catalogs that include proper-motion information, we have detected 26 stellar radio sources, doubling the number of such objects previously known in this region of high-latitude sky. We also show that, in the absence of good proper motions, even the 1" precision of the FIRST positions is insufficient to avoid crippling chance coincidence rates. We calculate the fraction of radio detections as a function of stellar magnitude and show that, when proper motions from the Guide Star Catalog II become available, the number of stellar radio source detections should increase fourfold.