Deviations from passive evolution - star formation and the ultraviolet excess in z similar to 1 radio galaxies0

K J Inskip, P N Best, M S Longair

Research output: Contribution to journalArticlepeer-review

Abstract

Galaxy colours are determined for two samples of 6C and 3CR radio sources at z similar to 1, differing by a factor of similar to 6 in radio power. Corrections are made for emission-line contamination and the presence of any nuclear point source, and the data analysed as a function of both redshift and the radio source properties. The galaxy colours are remarkably similar for the two populations, and the ultraviolet excess evolves with radio source size similarly in both samples, despite the fact that the alignment effect is more extensive for the more powerful 3CR radio galaxies. These results seem to suggest that the alignment effect at these redshifts does not scale strongly with radio power, and is instead more closely dependent on galaxy mass (which is statistically comparable for the two samples). However, it is likely that the presence of relatively young (less than or similar to several times 10(8)-yr-old) stellar populations has considerably contaminated the K-band flux of these systems, particularly in the case of the more powerful 3CR sources, which are similar to 0.5 mag more luminous than the predictions of passive evolution models at z similar to 1. The higher luminosity of the 3CR alignment effect is balanced by emission at longer wavelengths, thereby leading to comparable colours for the two samples.

Original languageEnglish
Pages (from-to)693-708
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume367
Issue number2
DOIs
Publication statusPublished - 1 Apr 2006

Keywords

  • galaxies : active
  • galaxies : evolution
  • galaxies : photometry
  • COMPACT STEEP-SPECTRUM
  • UKIRT IMAGING OBSERVATIONS
  • EMISSION-LINE GAS
  • HIGH-REDSHIFT
  • ELLIPTIC GALAXIES
  • DEEP SPECTROSCOPY
  • HYDRODYNAMIC INTERACTION
  • INFRARED OBSERVATIONS
  • CLUSTER ENVIRONMENTS
  • STELLAR POPULATIONS

Fingerprint

Dive into the research topics of 'Deviations from passive evolution - star formation and the ultraviolet excess in z similar to 1 radio galaxies0'. Together they form a unique fingerprint.

Cite this