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Title: | On the interpretation of the observed angular-size-flux-density relation for extragalactic radio sources |
Authors: | Kapahi, V.K. Subrahmanya, C.R. Kulkarni, V.K. |
Keywords: | Cosmology Extragalactic Radio Sources Radiant Flux Density Luminosity Red Shift Size Distribution |
Issue Date: | Mar-1987 |
Publisher: | Indian Academy of Sciences, Bangalore |
Citation: | Journal of Astrophysics and Astronomy, 1987, Vol. 8, p33 |
Abstract: | The interpretation of the observed relation between median angular sizes (thetam) of extragalactic radio sources and flux density at 408 MHz has been examined. The predicted thetam-S relations based on well-observed strong sources in parent samples selected at 178 and 1400 MHz, and existing models of the evolving radio luminosity function, can be made to fit the observed relation only by invoking cosmological evolution in linear sizes even for the q(0) = 0 universe. Predictions based on a parent sample at 2.7 GHz are shown to overestimate the contribution of steep-spectrum, compact (SSC) sources in low-frequency samples unless the downward curvature in the spectra of such sources is taken into account. When approximate corrections are made for this effect, predictions based on the 2.7 GHz parent sample cannot obviate the need for linear size evolution as claimed in the literature. |
Description: | Restricted Access. |
URI: | http://hdl.handle.net/2289/4234 |
ISSN: | 0250-6335 0973-7758 (online) |
Alternative Location: | http://adsabs.harvard.edu/abs/1987JApA....8...33K http://dx.doi.org/10.1007/BF02714250 |
Copyright: | 1987 Indian Academy of Sciences, Bangalore, India |
Appears in Collections: | Research Papers (A&A) |
Files in This Item:
File | Description | Size | Format | |
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1987_JApA_8_p33.pdf Restricted Access | Restricted access | 1.57 MB | Adobe PDF | View/Open Request a copy |
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