An Optical/Near-Infrared Study of Radio-Loud Quasar Environments II. Imaging Results

Abstract

We use optical and near-IR imaging to examine the properties of the significant excess population of K>=19 galaxies found in the fields of 31 z=1-2 radio-loud quasars by Hall, Green & Cohen (1998). The excess occurs on two spatial scales: a component at <40'' from the quasars significant compared to the galaxy surface density at >40'' in the same fields, and a component roughly uniform to ~100'' significant compared to the galaxy surface density seen in random-field surveys in the literature. The r-K color distributions of the excess galaxy populations are indistinguishable and are significantly redder than the color distribution of the field population. The excess galaxies are consistent with being predominantly early-type galaxies at the quasar redshifts, and there is no evidence that they are associated with intervening MgII absorption systems. The average excess within 0.5 Mpc (~65'') of the quasars corresponds to Abell richness class ~0 compared to the galaxy surface density at >0.5 Mpc from the quasars, and to Abell richness class ~1.5 compared to that from the literature. We discuss the spectral energy distributions (SEDs) of galaxies in fields with data in several passbands. Most candidate quasar-associated galaxies are consistent with being 2-3 Gyr old early-types at the quasar redshifts of z~1.5. However, some objects have SEDs consistent with being 4-5 Gyr old at z~1.5, and a number of others are consistent with ~2 Gyr old but dust-reddened galaxies at the quasar redshifts. These potentially different galaxy types suggest there may be considerable dispersion in the properties of early-type cluster galaxies at z~1.5. There is also a population of galaxies whose SEDs are best modelled by background galaxies at z>2.5.

Accepted to ApJ; 54 pages including 30 figures; 2 color GIF files available separately; also available from http://www.astro.utoronto.ca/~hall/thesis.html

References in corpus (17)

• A Large Structure of Galaxies At Redshift z~3 and its Cosmological Implications
• The Evolution of Early-Type Galaxies in Distant Clusters
• The Age Of Globular Clusters In Light Of Hipparcos: Resolving the Age Problem?
• Hubble Space Telescope imaging of the CFRS and LDSS redshift surveys II: Structural parameter and the evolution of disk galaxies to z=1
• Optical-IR Spectral Energy Distributions of z>2 Lyman Break Galaxies
• HST imaging of CFRS and LDSS galaxies - I: Morphological Properties
• HST, radio and infrared observations of 28 3CR radio galaxies at redshift z ~ 1: I. Old stellar populations in central cluster galaxies
• Galaxy-Galaxy Lensing in the Hubble Deep Field: The Halo Tully-Fisher Relation at Intermediate Redshift
• An IR-Selected Galaxy Cluster at z=1.27
• A maximum-likelihood method for improving faint source flux and color estimates
• The Norris Survey of the Corona Borealis Supercluster: III. Structure and Mass of the Supercluster
• Deep WFPC2 and Ground-based Imaging of a Complete Sample of 3C Quasars and Galaxies
• The ESO K'-band Galaxy Survey - Galaxy Counts
• Morphology and Surface Brightness Evolution of z\sim1.1 Radio Galaxies
• Infrared emission-line galaxies associated with damped Lyman-alpha and strong metal absorber redshifts
• The Clustering of K\sim 20 Galaxies on 17 Radio Galaxy Fields
• On the Dust Extinction in High-z Galaxies and the Case of Extremely Red Objects

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