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Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars

Wold, M. and Armus, L. and Neugebauer, G. and Jarrett, T. H. and Lehnert, M. D. (2003) Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars. Astronomical Journal, 126 (4). pp. 1776-1786. ISSN 0004-6256. doi:10.1086/378362.

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We have examined the occurrence of extremely red objects (EROs) in the fields of 13 luminous quasars (11 radio-loud and two radio-quiet) at 1.8 < z < 3.0. The average surface density of K_s ≤ 19 mag EROs is 2–3 times higher than in large, random-field surveys, and the excess is significant at the ≈3 σ level even after taking into account that the ERO distribution is highly inhomogeneous. This is the first systematic investigation of the surface density of EROs in the fields of radio-loud quasars above z ≈ 2 and shows that a large number of the fields contain clumps of EROs, similar to what is seen only in the densest areas in random-field surveys. The high surface densities and angular distribution of EROs suggest that the excess originates in high-redshift galaxy concentrations, possibly young clusters of galaxies. The fainter EROs at K_s ≳ 19 mag show some evidence of being more clustered in the immediate 20'' region around the quasars, suggesting an association with the quasars. Comparing with predictions from spectral synthesis models, we find that if the K_s ≈ 19 mag ERO excess is associated with the quasars at z ≈ 2, their magnitudes are typical of ≳ L* passively evolving galaxies formed at z ≈ 3.5 (Ω_m = 0.3, Ω_Λ = 0.7, and H_0 = 70 km s^(-1) Mpc^(-1)). Another interpretation of our results is that the excess originates in concentrations of galaxies at z ≈ 1 lying along the line of sight to the quasars. If this is the case, the EROs may be tracing massive structures responsible for a magnification bias of the quasars.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Armus, L.0000-0003-3498-2973
Jarrett, T. H.0000-0002-4939-734X
Lehnert, M. D.0000-0003-1939-5885
Additional Information:© 2003. The American Astronomical Society. Received 2003 May 22. Accepted 2003 July 9. We are grateful to Dave Thompson, Lin Yan, and Mark Lacy for helpful discussions, and to the referee for a careful review of the manuscript. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has also made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:galaxies: clusters: general; galaxies: high-redshift; infrared radiation ; quasars: general
Issue or Number:4
Record Number:CaltechAUTHORS:20170216-150046169
Persistent URL:
Official Citation:M. Wold et al 2003 AJ 126 1776
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74392
Deposited By: George Porter
Deposited On:17 Feb 2017 15:40
Last Modified:11 Nov 2021 05:26

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