The R-band Hubble diagram for gigahertz peaked spectrum radio galaxies

Open Access
Publisher Website
Google Scholar
Abstract
In this paper we show that the i?-band Hubble relation for gigahertz peaked spectrum (GpS) radio galaxies has a low dispersion and steep slope. It is comparable to that for first-ranked cluster galaxies, but spans a much greater redshift range. Its dispersion is significantly smaller than that of 3C radio galaxies. In addition, GPS galaxies are clearly fainter than 3C galaxies at z>0.5, probably because GPS galaxies are intrinsically redder. This may be due to GPS galaxies not having the extended UV-optical component that is present in high-redshift 3C galaxies. The GPS Hubble diagram is consistent with galaxies having an old stellar population that undergoes no cosmological evolution. However, it is possible that the dynamical evolution and stellar evolution of GPS galaxies fortuitously combine to produce a Hubble relation which is consistent with a non-evolutionary scenario. An alternative explanation is that GPS galaxies are in a special phase of their evolution, the ‘GpS’ phase, which is identical at all cosmological epochs.

This publication has 0 references indexed in Scilit: