2001/04/21 by P. Saracco, E. Giallongo, S. Cristiani +6 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20010795
13 pages, 9 figures, Accepted for publication in A&A
arxiv created 2001/04/21 · openalex publication_date 2001/08/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
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.