Volume 375, Number 1, August III 2001
|Page(s)||1 - 13|
|Published online||15 August 2001|
Deep near-IR observations of the Chandra Deep Field and of the HDF South*
Color and number counts
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, email@example.com
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
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.