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Extremely Red Objects in The Lockman Hole

G. Wilson·J. -S. Huang·P. G. Perez-Gonzalez·E. Egami·R. J. Ivison·J. R. Rigby·A. Alonso-Herrero·P. Barmby·H. Dole·G. G. Fazio·E. Le Floc'h·C. Papovich·D. Rigopoulou·L. Bai·C. W. Engelbracht·D. Frayer·K. D. Gordon·D. C. Hines·K. A. Misselt·S. Miyazaki·J. E. Morrison·G. H. Rieke·M. J. Rieke·J. Surace
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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.

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G. Wilson, J. -S. Huang, P. G. Perez-Gonzalez, E. Egami, R. J. Ivison, J. R. Rigby, A. Alonso-Herrero, P. Barmby, H. Dole, G. G. Fazio, E. Le Floc'h, C. Papovich, D. Rigopoulou, L. Bai, C. W. Engelbracht, D. Frayer, K. D. Gordon, D. C. Hines, K. A. Misselt, S. Miyazaki, J. E. Morrison, G. H. Rieke, M. J. Rieke, J. Surace. 2004-05-30. Extremely Red Objects in The Lockman Hole. https://doi.org/10.1086/422716

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