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VLA observations of unidentified Leiden-Berkeley Deep-Survey sources - Luminosity and redshift dependence of spectral propertiesVLA observations of a complete subset of the Leiden-Berkeley Deep Survey sources that have S(1.4 GHz) greater than 10 mJy and are not optically identified down to F=22 mag are reported. By comparing the spectral and structural properties of the sources with samples from the literature, an attempt was made to disentangle the luminosity and redshift dependence of the spectral indices of extended emission in radio galaxies and of the incidence of compact steep-spectrum sources. It is found that the fraction of compact sources among those with a steep spectrum is related primarily to redshift, being much larger at high redshifts for sources of similar radio luminosity. Only a weak and marginally significant dependence of spectral indices of the extended sources on luminosity and redshift is found in samples selected at 1.4 and 2.7 GHz. It is pointed out that the much stronger correlation of spectral indices with luminosity may be arising partly from spectral curvature, and partly due to the preferential inclusion of very steep-spectrum sources from high redshift in low-frequency surveys.
Document ID
19900046752
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kapahi, Vijay K.
(JPL Pasadena, CA, United States)
Kulkarni, Vasant K.
(Tata Institute of Fundamental Research Poona, India)
Date Acquired
August 14, 2013
Publication Date
May 1, 1990
Publication Information
Publication: Astronomical Journal
Volume: 99
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
90A33807
Distribution Limits
Public
Copyright
Other

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