Extragalactic Radio Quasars: Consequences of the Luminosity/ Redshift Relationship

Abstract

We have used both analytical and statistical methods to show some plausible consequences of the luminosity/redshift relationships for compact steep spectrum (CSS) quasars and the more extended extragalactic radio (EGR) quasars. From the analytical methods (or theory), we find that luminosity shows an inverse dependence on the redshift; while from the statistical (empirical) the converse is the case for both CSS quasars and their extended counterparts. We know that luminosity selection effects may play some role in the empirical results. However, we find that the magnitudes of departure of the two empirical results from the theoretical result are staggering – the difference for the extended EGR quasars far outweighs that of the CSS quasars. We may state categorically that this discrepancy may simply be a sign of a factor in the intergalactic medium (IGM) that appears to cause the anomaly in the extended EGR quasars. This is because sources with similar powers are expected to produce similar luminosities; and besides, central engines of the more extended EGR quasars have roughly similar powers with the CSS central engines. However, our results show great difference between their radiated powers (luminosities). A likely explanation of this is that the irregularity may be a signature of dark/vacuum energy. It simply indicates that among other factors, dark energy may constitute a factor which influences luminosities of the more extended EGR quasars. The components (jets and lobes) of the more extended EGR quasars lie in the intergalactic medium (IGM). This medium is more of a vacuum than the interstellar medium (ISM) in which the components of the CSS sources are located. Therefore, dark energy is expected to show more effect in the IGM than in the ISM. Besides, we estimate percentage influence caused by luminosity selection effect and that caused by the presumed dark/vacuum energy. The estimates are respectively,  and . These results show that intrinsically, dark/vacuum energy influences extended EGR quasars’ luminosities by about  times more than the observational bias caused by luminosity selection effects.