The Luminosity Function of Extragalactic Radio Sources.

Abstract

view Abstract Citations (12) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Luminosity Function of Extragalactic Radio Sources. Roeder, R. C. ; McVittie, G. C. Abstract The theory of relativistic model universes has been used as a basis for reanalyzing the data published by Minkowski in' his pioneer attempt to the luminosity function of extragalactic radio sources. The theory has been used to develop the relation between the optical and radio distance moduli of any galaxy. Approximations enabling the red shift of a galaxy to be calculated from either its optical or its radio distance modulus have been found for model universes having zero cosmical constant. The volume of space contained within the distance corresponding to a given red shift has been expressed, for these models, in terms of the red shift, the Hubble parameter, and the acceleration factor. The foregoing theory using a model universe having zero cosmical constant and positive spatial curvature has been applied to fifty identified extragalactic radio sources with three sets of values for the acceleration factor and first-order K-correction coefficient. The result is a luminosity function, fli(Mr), of the form log fli(Mr) = 0 51 Mr + b, where b depends upon the acceleration factor and first-order K- correction coefficient. These representations of the function have each been used to construct an "N-S" curve. The theoretical curves, however, predic't too few sources at faint flux densities and their curvature disagrees with the linearity of the observational results. It is suggested that incompleteness of the identifications is partly responsible for this lack of agreement. It is also pointed out that the value assumed for the cosmical constant is an approximation and that adopting a more accurate value might enable agreement to be achieved without abandoning the second assumption used-that the number of sources per unit volume of the co-moving coordinate system remains constant in time. Publication: The Astrophysical Journal Pub Date: November 1963 DOI: 10.1086/147695 Bibcode: 1963ApJ...138..899R full text sources ADS | data products NED (41)