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VLA M 31 1.4-GHz Source Catalog

Published by High Energy Astrophysics Science Archive Research Center | National Aeronautics and Space Administration | Metadata Last Checked: October 19, 2025 | Last Modified: 2025-09-10
This table contains the Data Release 2 of the Point Source Catalog created from a series of previously constructed radio-continuum images of M 31 at a wavelength lambda of 20 cm (frequency nu = 1.4 GHz) from archived VLA observations. In total, the authors identify a collection of 916 unique discrete radio sources across the field of M 31. Comparing these detected sources with those listed by Gelfand et al. (2004, ApJS, 155, 89, HEASARC table VLAM31325M) at lambda = 92 cm (325 MHz), the spectral index of 98 sources has been derived. The majority (73%) of these sources exhibit a spectral index of alpha < -0.6, indicating that their emission is predominantly non-thermal in nature, which is typical for background objects and Supernova Remnants (SNRs). This table contains the integrated flux densities for 1,131 detections of 916 unique sources detected at 1.4 GHz in 28 VLA observations. Of these 916 unique sources, 109 were detected in at least two separate images. For such sources, the authors list a group identifier, a group count, and an average flux and error. Sources were cross referenced with the Gelfand et al. (2004) catalog of sources detected at 92 cm. For matched sources, the flux density at this wavelength and the derived spectral index between 20 and 92 cm are listed. This table was created by the HEASARC in May 2015 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/Other/Ser/189.15">CDS Catalog J/Other/Ser/189.15</a> file m31radio.dat. This is a service provided by NASA HEASARC .

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