Galaxies in the Fields of z ∼ 1 . 5 Radio - Loud Quasars

We have previously identified an excess population of predominantly red galaxies around a sample of 31 radio-loud quasars (RLQs) at 1 < z < 2. Here we show that these fields have a surface density of extremely red objects (EROs, with R − K > 6) 2.7 times higher than the general field. Assuming these EROs are passively evolved galaxies at the quasar redshifts, they have characteristic luminosities of only ∼ L. Only one of four RLQ fields has an excess of J−K selected EROs with J−K > 2.5; thus, those objects are mostly unrelated to the quasars. We also present new multiwavelength data and analyses on the fields of four of these quasars at zq ∼ 1.54, obtained to build more detailed pictures of the environments of these quasars and the galaxies within them. First, wide-field J and Ks data shows that the galaxy excess around Q 0835+580 is of Abell richness 2±1 and extends to 140, and that the galaxy excess around Department of Astronomy, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8, Canada California Institute of Technology, Mail Stop 320-47, Pasadena, CA 91125 Astronomy Department, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210-1173 Steward Observatory, The University of Arizona, Tucson, AZ 85721 Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6, Canada Hubble Fellow Visiting Astronomer, Infrared Telescope Facility, operated by the University of Hawaii under contract to the National Aeronautics and Space Administration. Visiting Astronomer, Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii. Visiting Astronomer, James Clerk Maxwell Telescope, operated by The Joint Astronomy Centre on behalf of the Particle Physics and Astronomy Research Council of the United Kingdom, the Netherlands Organisation for Scientific Research, and the National Research Council of Canada. Current Address: Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, NY 11794-3800 Current Address: Carnegie Observatories, 813 Santa Barbara St., Pasadena, CA 91101 Current Affiliations: Princeton University Observatory, Princeton, NJ 08544-1001 and Pontificia Universidad Católica de Chile, Departamento de Astronomı́a y Astrof́ısica, Facultad de F́ısica, Casilla 306, Santiago 22, Chile; E-mail: [email protected]