The Photometric Redshift Distribution and Evolutionary Properties of Galaxies up to [CLC][ITAL]z[/ITAL][/CLC] ∼ 4.5 in the Field of the Quasar BR 1202−0725

We present a deep BVrIK multicolor catalog of galaxies in the field of thehigh redshift (z=4.7) quasar BR 1202-0725. Reliable colors have been measuredfor galaxies selected down to R=25. The choice of the optical filters has beenoptimized to define a robust multicolor selection of galaxies at 3.81.5. Atvariance with brighter surveys (I<22.5) there is a tail in the distributiontowards high redshifts up to z~4. The luminosity function at z~0.6 shows asteepening for M_B>-19. The observed cosmological ultraviolet luminositydensity is computed in the overall redshift interval z=0.3-4.5 reaching a value2x10^{19} W/Hz/Mpc^3 at z~0.8. We have derived in a homogeneous way, using theGISSEL libraries, the physical parameters connected with the fitted spectralenergy distributions. The bulk of the blue intermediate redshift populationwith z=0.4-1 mostly consists of very young star-forming galaxies with a medianstarburst age of the order of a few 10^8 yr and typical mass in luminous stars~2x10^8 Mo.Comment: 14 pages, 3 tables, 11 figures, Astronomical Journal in pres