The Surface Density of Extremely Red Objects
Abstract
We present initial results from a field survey for extremely red objects (EROs, defined here as (R-K') >= 6 mag) covering 154 square arcminutes of sky, from the first of 7 deep, wide-field K' images obtained as part of the Calar Alto Deep Imaging Survey (CADIS). The 5-sigma point source detection limits are K'=20.5 and R=25.0, while extended-source limits are up to 0.5-0.75 mag brighter. We identify a total of 8 bright EROs with K' =< 19.0. Six of these bright EROs are resolved and are likely to be galaxies, while the remaining 2 are unresolved, with colors consistent with their being low-mass galactic stars. We derive a surface density for the 6 bright, extragalactic EROs of 0.039 +/- 0.016 per sq. arcmin, higher by a factor of 4 than previous values. We estimate that the volume density of bright EROs to be as high as that of nearby Seyfert galaxies.
Keywords
Cite
@article{arxiv.astro-ph/9907216,
title = {The Surface Density of Extremely Red Objects},
author = {D. Thompson and S. V. W. Beckwith and R. Fockenbrock and J. Fried and H. Hippelein and J. -S. Huang and B. von Kuhlmann and Ch. Leinert and K. Meisenheimer and S. Phleps and H. -J. Röser and E. Thommes and C. Wolf},
journal= {arXiv preprint arXiv:astro-ph/9907216},
year = {2009}
}
Comments
19 pages, including 5 figures and 2 tables. To appear in ApJ