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For refcode 1988MNRAS.230..131P:
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Copyright by Royal Astronomical Society. 1988MNRAS.230..131P The cluster environments of powerful radio galaxies Richard M. Prestage Department of Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ John A. Peacock Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ Accepted 1987 August 6. Received 1987 August 4; in original form 1987 June 1 Summary. We have used the technique of angular cross-correlation to estimate the local galaxy density around powerful radio galaxies. Our results are based on the Lick galaxy counts for z<0.1, with deep galaxy samples from UK Schmidt plates scanned with COSMOS used to extend the range to z<0.25. We analyse the errors in the derived clustering strengths, including the effect of photometrically estimated redshifts. Results in the form of the ratio of the spatial cross-correlation amplitude (B_gg^*^_) to the autocorrelation amplitude for galaxies in general (B_gg_) are given for ~200 radio sources, from which several important trends are evident: (i) As was well-known, the low-luminosity sources of Fanaroff-Riley class I lie on average in richer clusters than those of class II. There appears, however, to be a real scatter in properties: cluster strength is not the sole factor governing structure. (ii) We find no strong statistical evidence for the difference in environment which was previously suggested to exist between different sub-classes of the class II sources. (iii) Compact radio sources appear to lie in regions of low galaxy density, with (B_gg^*^_/B_gg_) a factor of >~2 lower than for Fanaroff-Riley class I sources (and possibly even slightly lower than for Fanaroff-Riley class II sources). This result may pose a severe problem for unified relativistic beaming models. ########################################################################## 1989MNRAS.236..959P Erratum: The cluster environments of powerful radio galaxies ************* by Richard M. Prestage and John A. Peacock The paper `The cluster environments of powerful radio galaxies', by Richard M. Prestage and John A. Peacock was published in Mon. Not. R. astr. Soc., (1988) 230, 131-160. There was an error in the function H(z) used in this paper, which was too large by a factor (180/{pi})^2-{gamma}^. Consequently, all quoted values of B_gg*_ (Tables 5-7) are too small and should be increased by this same factor which amounts to 2.537 for the adopted value of {gamma}=1.77. The value for B_gg_ is similarly affected; however, there was an additional error in the computer program which converted between A_gg_ and B_gg_. This increased the B_gg_. value by a factor of almost exactly 2, approximately cancelling the effect of the above error in H(z). After these corrections, the value of B_gg_ deduced from the Lick counts becomes 51. Thus, the values of B_gg*_/B_gg_ (Table 4) are too small and should be doubled. The discussion of the richness of radio galaxy environments remains unaltered. B_gg*_ values for Abell clusters were evaluated using the same method as for the radio galaxies, so the above global scaling factors do not affect the richness values inferred for the radio galaxies.
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