Open AccessThe cosmic evolution of low‐luminosity radio sources from the Sloan Digital Sky Survey Data Release 1
Author(s) -
Clewley L.,
Jarvis Matt J.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07981.x
Subject(s) - physics , sky , astrophysics , luminosity , redshift , astronomy , luminosity function , cosmic cancer database , source counts , population , galaxy , demography , sociology
In this paper we constrain the evolution in the comoving space density for low‐luminosity [typically Fanaroff–Riley type I (FRI)] radio sources as a function of cosmic epoch by matching deep radio surveys [Westerbork Northern Sky Survey (WENSS), Faint Images of the Radio Sky at Twenty‐centimetres (FIRST) and NRAO VLA Sky Survey (NVSS)] with the Sloan Digital Sky Survey (SDSS). This results in 1014 matched radio sources covering an effective area of 0.217 sr, 686 with L 325 MHz < 10 25 W Hz −1 sr −1 , which is an order of magnitude larger than any previous study at these luminosities. Using the non‐parametric V / V max test we show that low‐luminosity radio sources evolve differently from their more powerful, predominantly Fanaroff–Riley type II (FRII), counterparts. Indeed, we find that the lower luminosity population is consistent with a constant comoving space density with redshift, as opposed to the strong positive evolution for the more powerful sources.