The surface density of Extremely Red Objects in high- z quasar fields

We report on a study of the surface density of Extremely Red Objects (EROs) in the fields of 13 quasars at 1.8< z<3.0 covering a total area of 61.7 arcmin 2. There is a large variation in the ERO surface density from field to field, and as many as 30–40% of the fields have roughly 4–5 times mo...

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Bibliographic Details
Published inNew astronomy reviews Vol. 47; no. 4; pp. 321 - 324
Main Authors Wold, M., Armus, L., Neugebauer, G., Jarrett, T.H., Lehnert, M.D.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.09.2003
Subjects
Galaxies: clusters
Quasars: gravitational lensing
Quasars: gravitational lensing
Galaxies: clusters
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Summary:We report on a study of the surface density of Extremely Red Objects (EROs) in the fields of 13 quasars at 1.8< z<3.0 covering a total area of 61.7 arcmin 2. There is a large variation in the ERO surface density from field to field, and as many as 30–40% of the fields have roughly 4–5 times more EROs than what is expected from a random distribution. The average surface density exceeds the value found in large random-field surveys by a factor of 2–3, a result which is significant at the >3 σ level. Hence, it appears that the quasar lines of sight are biased towards regions of high ERO density. This might be caused by clusters or groups of galaxies physically associated with the quasars. However, an equally likely possibility is that the observed ERO excess is part of overdensities in the ERO population along the line of sight to the quasars. In this case, the non-randomness of quasar fields with respect to EROs may be explained in terms of gravitational lensing.
ISSN:1387-6473
1872-9630
DOI:10.1016/S1387-6473(03)00046-0