Radio-loud Quasars and Expansion of Universal Space-time

Abstract

We have employed both analytical methods and statistical methods to find possible constraints that may be imposed by the observed accelerated expansion of the space-time on radio-loud quasars. We have done this by carrying out linear regression analysis on large-sized (linear size, ) quasars and on their smaller (more compact) (linear size, ) counterparts in our sample. On the linear size/redshift plane for the larger quasars, we find that these sources expand as space-time expands. Though they show similar trend on the  plot, their more compact counterparts however, indicate difference in their gradient. The result of the more compact sources shows steeper slope , while that of the more extended sources indicates a flatter slope . This discrepancy must have originated from the ambient environments in which they are sited since the two sub-classes of objects have been shown to be situated in different ambient media. So, their observable physical processes should not be expected to be precisely the same. Therefore, since the compact sources are generally sub-galactic in dimensions (i.e. linear sizes are below ), they are affected more by their denser ambient media. Also, gravity is more noticeable within a typical galaxy (and diameter of a typical galaxy is about ) than within the intergalactic medium; so, space expansion should unsurprisingly yield little or null effect on the evolution of these compact sources. This is shown in our obtained relation, . It indicates that the observed universal space-time expansion causes little or no effects on the sizes of these more compact quasars, and hence, their evolution is largely dynamical; while the converse may be the case for the more extended quasars. Conclusively, we state that large-sized radio-loud quasars are intergalactic which implies they are neither held by gravity nor dense media, but more possibly affected by creation of more spaces due to dark energy accelerating expansion of the universe. In contrast with it, Compact Steep Spectrum (CSS) quasars which are generally sub-galactic possibly get affected by denser ambient gases and gravity within CSS quasars, have little or no effect on source growth by dark energy.