VLA observations of steep-spectrum, variable radio sources

Abstract

view Abstract Citations (9) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS VLA observations of steep-spectrum, variable radio sources Spangler, S. R. ; Cook, D. B. Abstract Observations made by the Very Large Array (VLA) of 15 steep-spectrum radio sources previously reported to be variable at 2.7 GHz are presented. Data obtained in the C and L bands with angular resolutions of 0.7 and 2.4 arcsec was analyzed by the construction of visibility plots and interferometer maps. In six of the sources, compact components which could be responsible for the observed variability have not been detected, and upper limits to the fraction of source flux in an unseen variable component are determined. In the remaining nine cases, compact components were observed and their flux densities determined, and analysis of the variability parameters shows them to be similar to those of the more common flat-spectrum variable radio sources. The presumed sources of variability in the objects lacking compact components, however, are concluded to be much more active than known extragalactic variables. Publication: The Astronomical Journal Pub Date: June 1980 DOI: 10.1086/112724 Bibcode: 1980AJ.....85..659S Keywords: Antenna Arrays; Extragalactic Radio Sources; Periodic Variations; Radio Astronomy; Spectrum Analysis; Angular Resolution; Astronomical Maps; Radiant Flux Density; Radio Emission; Radio Interferometers; Superhigh Frequencies; Ultrahigh Frequencies; Very Large Array (Vla); Astronomy full text sources ADS | data products NED (14)