1996/06/06 by B. Fort, Y. Mellier, Fort, B. +3
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9606039
Latex, 11 pages, l-aa.sty and psfig.sty, 10 figures. 187K gzipped tar file. Submitted to Astronomy & Astrophysics Main Journal
arxiv created 1996/06/06 · arxiv updated 2016/08/30
We analyse the surface density of very faint galaxies at the limit of the sky background noise in the field of the cluster of galaxies Cl0024+1654. The radial variation of their number density in the magnitude bins B=26-28 and I=24-26.5 displays an (anti)bias magnification effect for I < 24 which provides the redshift range of the populations seen in B and I. The depletion curve can be reproduced with two redshift populations with 60% ± 10% of the B galaxies between z=0.9 and z=1.1 and the remaining at a redshift close to z=3. The I selected population is similar but with a minimum extending from the B inner critical line to RI=60". Whatever the cosmological model, the I-selected galaxies spread up to a larger redshift with about 20% above z > 4. Using a model for the gravitational potential, the locations of the two extreme critical lines for the B and I galaxies favour ΩΛ-dominated flat universes with a cosmological constant ranging from 0.6 to 0.9. The result is confirmed by a preliminary investigation of A370. We discuss the method to search the "last critical line" and the various biases.