Submillimeter properties of extremely red objects.
WEHNER E.H., BARGER A.J. and KNEIB J.-P.
Abstract (from CDS):
We use deep near-infrared and submillimeter observations of three massive lensing cluster fields, A370, A851, and A2390, to determine the average submillimeter properties of a K'-selected sample. The 38 extremely red objects (EROs; I-K'>4) with K'<21.25 have a very significant error-weighted mean 850 µm flux of 1.58±0.13 mJy. The ERO contribution to the 850 µm background is (1.88±0.16)x104 mJy.deg–2, or about half the background light. The 17 very red objects (VROs; 3.5<I-K'<4) are also significantly detected (1.32±0.19 mJy), bringing the combined VRO and ERO contribution to (2.59±0.19)x104 mJy.deg–2. There is a substantial systematic uncertainty (about a factor of 2) in this value due to field-to-field variation, but even with this uncertainty it is clear that a large fraction of the 850 µm background arises from red objects. An analysis of the VRO and ERO number counts shows that half of the population's 850 µm light arises in objects with demagnified magnitudes K'<20, and half in fainter objects. On the basis of the I-J versus J-K' colors of the galaxies, the bulk of the submillimeter signal appears to arise from the dusty starburst galaxies in the red object population rather than from the high-redshift elliptical galaxies.