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Hard X–ray observations of Extremely Red Objects
Author(s) -
Brusa M.
Publication year - 2003
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200310029
Subject(s) - physics , astrophysics , galaxy , redshift , flux (metallurgy) , astronomy , active galactic nucleus , x ray , optics , materials science , metallurgy
Extremely Red Objects (EROs, R–K>5) constitute a heterogeneous class of extragalactic sources including high redshift elliptical galaxies, dusty star–forming systems and heavily obscured AGNs. Hard X‐ray observations provide an unique and powerful tool to uncover obscured nuclear or star–forming activity. We present the results of XMM– Newton observations of the largest sample of EROs available to date (about 450 objects over a contiguous area of 700 arcmin 2 ). Five of the 46 hard X–ray selected sources brighter than 3 × 10 –15 cgs in the 2–10 keV band, are associated with EROs. All of the X‐ray detected EROs show rather extreme X–ray–to–optical flux ratios, suggesting the presence of highly obscured AGN activity.We also report on the X–ray stacking analysis of spectroscopically identified EROs in the Chandra Deep Field South.