World Library  
Flag as Inappropriate
Email this Article

Second Cambridge Catalogue of Radio Sources

Article Id: WHEBN0001601343
Reproduction Date:

Title: Second Cambridge Catalogue of Radio Sources  
Author: World Heritage Encyclopedia
Language: English
Subject: Source counts, Cambridge Interferometer, 2C, Third Cambridge Catalogue of Radio Sources, Sixth Cambridge Survey of radio sources
Collection: Cambridge Surveys of Radio Sources
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Second Cambridge Catalogue of Radio Sources

2C
Organization Radio Astronomy Group, University of Cambridge
Wavelength 81.5 MHz radio
Data sources Cambridge Interferometer
Data products 2C Catalogue

The Second Cambridge Catalogue of Radio Sources (2C) was published in 1955 by John R Shakeshaft and colleagues. It comprised a list of 1936 sources between declinations -38 and +83, giving their right ascension, declination, both in 1950.0 coordinates, and flux density. The observations were made with the Cambridge Interferometer, at 81.5 MHz.

The data appeared to show a flux/number ('source counts') trend which precluded some cosmological models (such as the Steady-State):-

For a uniform distribution of radio sources the slope of the cumulative distribution of log(number, N) versus log (power, S) would have been -1.5, but the Cambridge data apparently implied a (log(N),log(S)) slope of nearly -3.0.

Unfortunately, this interpretation appears to have been premature - a significant number of the sources listed were later found to be the product of 'confusion', the blending of several weaker sources in the lobes of the interferometer to produce the apparent effect of a single stronger source. (Key data demonstrating this came from the then-recently commissioned Mills Cross Telescope in Australia).

However, subsequent statistical analysis by Hewish of the interferometer records later showed some aspects of the initial interpretation to have been broadly correct.

The survey was superseded by the much more reliable 3C and 3CR surveys. The 3C survey also used the Cambridge Interferometer, but at 159 MHz, which helped significantly reduce the 'confusion' (see above) in the later survey.

References


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.