Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 2003 | Published + Accepted Version
Journal Article Open

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

Abstract

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.

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.

Attached Files

Published - Wold_2003_AJ_126_1776.pdf

Accepted Version - 0307224.pdf

Files

Wold_2003_AJ_126_1776.pdf
Files (660.0 kB)
Name Size Download all
md5:a0d6182e82a73cf3e419046d9d42ed2d
314.9 kB Preview Download
md5:ef064f693432e9a4c9dee6cf94128d7e
345.1 kB Preview Download

Additional details

Created:
September 15, 2023
Modified:
October 23, 2023