English

The environment of active objects in the nearby universe

Astrophysics 2009-11-07 v1

Abstract

We study the galaxy environment of active galaxies, radio-loud and radio-quiet quasars in the redshift range 0.1z0.250.1\leq z\leq0.25. We use APM galaxies in order to explore the local galaxy overdensity and the bJRb_J-R colour distribution of neighbouring galaxies of these target samples. For comparison, we perform similar analysis on samples of Abell clusters with X-ray emission, and samples of Abell clusters with richness R=1 and R=0. The projected cross-correlations show that the samples of quasars and active galaxies reside in regions of galaxy density enhancements lower than those typical of R=0 clusters. We also find that in the nearby universe the local galaxy overdensity of radio-loud and radio-quiet quasars are comparable. The analysis of the distribution of bJRb_J-R galaxy colour indexes suggests that the environment of quasars is not strongly dominated by a population of red galaxies, characteristic of rich Abell cluster, an effect that is more clearly appreciated for our sample of radio-loud quasars.

Keywords

Cite

@article{arxiv.astro-ph/0205409,
  title  = {The environment of active objects in the nearby universe},
  author = {Georgina V. Coldwell and Hector J. Martinez and Diego G. Lambas},
  journal= {arXiv preprint arXiv:astro-ph/0205409},
  year   = {2009}
}

Comments

5 pages, 3 figures, to appear in MNRAS