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Extremely Red Objects in the Lockman Hole
- Source :
- The Astrophysical Journal Supplement Series. 154
- Publication Year :
- 2004
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 2004.
-
Abstract
- We investigate extremely red objects (EROs) using near- and mid-infrared observations in five passbands (3.6 to 24 microns) obtained from the Spitzer Space Telescope, and deep ground-based R and K imaging. The great sensitivity of the Infrared Array Camera (IRAC) camera allows us to detect 64 EROs (a surface density of 2.90 +/- 0.36 arcmin(exp -2); [3.6](sub AB) is less than 23.7) 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 greater than 1.3 EROs. We find approximately 17% of all galaxies detected by IRAC at 3.6 or 4.5 microns to be EROs. These percentages rise to about 40% at 5.8 microns, and about 60% at 8.0 microns. We utilize the spectral bump at 1.6 microns to divide the EROs into broad redshift slices using only near-infrared colors (2.2/3.6/4.5 microns). We conclude that two-thirds of all EROs lie at redshift z greater than 1.3. Detections at 24 microns imply that at least 11% of 0.6 less than z and less than 1.3 EROs and at least 22% of z greater than 1.3 EROs are dusty star-forming galaxies.
- Subjects :
- Astrophysics
Subjects
Details
- Language :
- English
- Volume :
- 154
- Database :
- NASA Technical Reports
- Journal :
- The Astrophysical Journal Supplement Series
- Notes :
- JPL-960541
- Publication Type :
- Report
- Accession number :
- edsnas.20080032493
- Document Type :
- Report
- Full Text :
- https://doi.org/10.1086/422716