Open AccessA complete sample of radio sources in the North Ecliptic Cap, selected at 38 MHz – III. Further imaging observations and the photometric properties of the sample
Author(s) -
Lacy Mark,
Kaiser Mary Elizabeth,
Hill Gary J.,
Rawlings Steve,
Leyshon Gareth
Publication year - 1999
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 - 10.1046/j.1365-8711.1999.02789.x
Subject(s) - physics , astrophysics , redshift , luminosity , astronomy , galaxy , cosmology , cosmic distance ladder , radio galaxy , flux (metallurgy) , materials science , metallurgy
Further imaging observations of a sample of radio sources in the North Ecliptic Cap are presented and a number of new identifications are made. Using redshifts from spectroscopic data presented in a companion paper by Lacy et al., the photometric properties of the galaxies in the sample are discussed. It is shown that: (1) out to at least z ≈0.6 radio galaxies are good standard candles irrespective of radio luminosity; (2) for 0.6≲ z ≲1 a large fraction of the sample has magnitudes and colours consistent with a non‐evolving giant elliptical, and (3) at higher redshifts, where the R ‐band samples the rest‐frame UV flux, most objects have less UV luminosity than expected if they form their stellar populations at a constant rate from a high redshift to z ∼1 in unobscured star‐forming regions (assuming an Einstein–de Sitter cosmology). The consequences of these observations are briefly discussed.