Issue |
A&A
Volume 375, Number 1, August III 2001
|
|
---|---|---|
Page(s) | 1 - 13 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361:20010795 | |
Published online | 15 August 2001 |
Deep near-IR observations of the Chandra Deep Field and of the HDF South*
Color and number counts
1
Osservatorio Astronomico di Brera, via E. Bianchi 46, Merate, Italy
2
Osservatorio Astronomico di Roma, via Dell'Osservatorio 2, Monteporzio, Italy
3
Space Telescope European Coordinating Facility, ESO, Karl-Schwarzschildstr. 2, Garching bei Munchen, Germany
4
Dipartimento di Astronomia, Universitá di Padova, Vicolo dell'Osservatorio, 2, Padova, Italy
5
ESO, Karl-Schwarzschildstr. 2, Garching bei Munchen, Germany
Corresponding author: P. Saracco, saracco@merate.mi.astro.it
Received:
20
December
2000
Accepted:
4
April
2001
We present near-IR (J and Ks) number counts and colors of galaxies
detected in deep VLT-ISAAC images centered on the
Chandra Deep Field and Hubble Deep Field-South for a total
area of 13.6 arcmin2.
The limiting surface brightness obtained is mag/arcsec2
and
(1σ) on both fields.
A d
/dm relation with a slope of ~0.34 in J and ~0.28
in Ks is found in both fields with no evidence of decline near the
magnitude limit.
The median
color of galaxies becomes bluer at magnitudes fainter
than
, in agreement with the different number counts slope
observed in the two bands.
We find a fraction (≤5% of the total sample) of sources
with color redder than
at magnitudes
.
Most of them appear as isolated sources, possibly elliptical
or dusty starburst galaxies at redshift
.
The comparison of the observed number counts with models shows that
our J-band and Ks-band counts are consistent with the prediction
of a model based on a small amount of merging in a
cosmology.
On the other hand, we fail to reproduce the
observed counts if we do not consider merging independently
of the parameters defining the universe.
Key words: cosmology: large-scale structure of Universe / galaxies: general
© ESO, 2001
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