Extremely Red Objects in The Lockman Hole
Abstract
We investigate Extremely Red Objects (EROs) using near- and mid-infrared observations in five passbands (3.6 to 24 micron) obtained from the Spitzer Space Telescope, and deep ground-based R and K imaging. The great sensitivity of the IRAC camera allows us to detect 64 EROs in only 12 minutes of IRAC exposure time, by means of an R-[3.6] color cut (analogous to the traditional red R-K cut). A pure infrared K-[3.6] red cut detects a somewhat different population and may be more effective at selecting z > 1.3 EROs. We find 17% of all galaxies detected by IRAC at 3.6 or 4.5 micron to be EROs. These percentages rise to about 40% at 5.8 micron, and about 60% at 8.0 micron. We utilize the spectral bump at 1.6 micron to divide the EROs into broad redshift slices using only near-infrared colors (2.2/3.6/4.5 micron). We conclude that two-thirds of all EROs lie at redshift z > 1.3. Detections at 24 micron imply that at least 11% of 0.6 < z < 1.3 EROs and at least 22% of z > 1.3 EROs are dusty star-forming galaxies.
Cite
@article{arxiv.astro-ph/0405612,
title = {Extremely Red Objects in The Lockman Hole},
author = {G. Wilson and J. -S. Huang and P. G. Perez-Gonzalez and E. Egami and R. J. Ivison and J. R. Rigby and A. Alonso-Herrero and P. Barmby and H. Dole and G. G. Fazio and E. Le Floc'h and C. Papovich and D. Rigopoulou and L. Bai and C. W. Engelbracht and D. Frayer and K. D. Gordon and D. C. Hines and K. A. Misselt and S. Miyazaki and J. E. Morrison and G. H. Rieke and M. J. Rieke and J. Surace},
journal= {arXiv preprint arXiv:astro-ph/0405612},
year = {2009}
}
Comments
to appear in the special Spitzer issue of the ApJS