- Third Cambridge Catalogue of Radio Sources
Infobox Astronomical survey
name = 3C
caption =
organization = Radio Astronomy Group,University of Cambridge
alt_names =
wavelength = 159 MHz radio
source =Mullard Radio Astronomy Observatory
goals = First detailed survey of radio sources
products = 3C Catalogue
website = [http://cdsweb.u-strasbg.fr/viz-bin/Cat?VIII/1A 3C and 3CR catalogues]The Third Cambridge Catalogue of Radio Sources (3C) is an
astronomical catalogue of celestial radio sources detected originally at 159 MHz, and subsequently at 178 MHz. It was published in1959 by members of the Radio Astronomy Group of theUniversity of Cambridge . References to entries in this catalogue in the scientific literature use the prefix 3C followed by the entry number, with a space, e.g.3C 273 . The catalogue was produced using theCambridge Interferometer on the west side ofCambridge . (The interferometer had previously been used for the 2C survey, published in 1955.)The catalogue was subsequently revised by Bennett in 1962 using observations at 178 MHz, and for many years '3CR' was considered as the definitive listing of the brighter radio sources in the Northern Hemisphere. The revision resulted in a number of sources being deleted from the catalogue (as being below the flux limit of 9 Jy or as now-resolved blends of adjacent sources) and others being added. To avoid renumbering the existing sources (which were listed in RA order) these new sources were added using a decimal extension. Eg.
3C 323.1 follows3C 323 inRight Ascension and precedes3C 324 .A further revision by Laing, Riley and Longair in 1983, called 3CRR or 3CR², included galaxies which were not detected in the original catalogue due to shortcomings of the original observations, but which otherwise meet the flux and declination limits. This new catalogue, which includes all extragalactic radio sources with 178-MHz flux density > 10.9 Jy (on the scale of Baars et al), declination greater than 10 degrees, and Galactic latitude greater than 10 degrees or less than -10 degrees, is formally a complete sample of radio galaxies and radio loud
quasar s. It excludes a number of well known 3C/3CR objects, including, of course, all the supernova remnants from 3C, but also some well-known radio galaxies that fall foul of the declination, flux density or galactic latitude constraints. Objects that had been discovered to consist of multiple components associated with different objects were given an alphabetical suffix (A, B...) to make it clear which component was part of the sample: e.g. the radio galaxy3C 66B is part of the sample, but theBL Lac object 3C 66A is not.ee also
External links
* [http://cdsweb.u-strasbg.fr/viz-bin/Cat?VIII/1A The Revised 3C Catalogue of Radio Sources] on the internet.
* [http://3crr.extragalactic.info/ The 3CRR catalogue on the internet.]References
*Edge, D. O., Shakeshaft, J. R., McAdam, W. B., Baldwin, J. E., & Archer, S. 1959, Mem. R. Astron. Soc., 68, 37, 'A survey of radio sources at a frequency of 159 Mc/s'
*Bennett A. S., 1962, MNRAS, 125, 75-86
*Laing R.A., Riley J.M., Longair M.S., 1983, MNRAS, 204, 151
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