Issue |
A&A
Volume 421, Number 3, July III 2004
|
|
---|---|---|
Page(s) | 821 - 832 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20035842 | |
Published online | 29 June 2004 |
Number counts of bright extremely red objects: Evolved
massive galaxies at z
1
European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago, Chile
2
Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
3
Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK
4
Observatory, PO Box 14, 00014 University of Helsinki, Finland
Corresponding author: P. Väisänen, pvaisane@eso.org
Received:
10
December
2003
Accepted:
8
April
2004
We present results on number counts of Extremely Red Objects
(EROs) in a 2850 arcmin2 near-infrared survey performed in
European Large Area ISO Survey (ELAIS) fields at . Counts
of EROs are extended to brighter levels than available previously,
giving
at
and consistent
numbers with literature values at fainter magnitudes.
Photometric redshifts from HYPERZ as well as GRASIL
model SEDs of galaxies imply that our EROs are located in the range
, with the bulk of the population at
.
Taking advantage of the ISO data in the fields, we use mid-IR
detections to constrain the number of
dusty EROs, and also discuss the superior capabilities of Spitzer
Space Telescope to
detect dusty EROs. Both the mid-IR data and the use of colour-colour
diagrammes indicate that at most 10-20% of the EROs in this bright
regime are dusty starbursting systems. The space density of
our EROs, interpreted to be counterparts of local
massive galaxies at around
, is estimated to be
, which is consistent with
local values. Furthermore, the cumulative number counts at our
bright magnitudes are remarkably well fitted by pure luminosity
evolution models.
Key words: galaxies: evolution / galaxies: formation / infrared: galaxies / cosmology: observations / galaxies: starburst / galaxies: elliptical and lenticular, cD
© ESO, 2004
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