Near-Infrared Galaxy Surveys in 2D, 3D & 4D

Abstract

The completeness and reliability of the DENIS IJK survey and the EDSGC (derived from the COSMOS scans of USKT plates) are obtained by detailed cross-identifications and systematic visual inspections of conflictual classifications. The DENIS galaxy extraction turns out to be over 95% complete and reliable out to I < 16, while the COSMOS/EDSGC galaxy catalogue is less than 80% complete and reliable at B_J = 17.5, and even less than 10% complete at B_J < 14.5. Spectroscopic followups of DENIS and the similar Near-IR 2MASS survey are described: 1) a redshift survey of 120,000 galaxies using the 6dF robotic multi-fiber spectrograph, currently under construction at the UKST, and for which a total of 300 nights are guaranteed for 2001-2003, 2) a peculiar velocity survey of 12,000 early-type galaxies with the 6dF, and 3) the DENIS-HI peculiar velocity survey of 5000 inclined spirals visible from Nancay (delta > -38 deg), which has just begun. The DENIS-HI and 6dF peculiar velocity samples will have the strong advantage of covering entire regions of the southern sky, and combined, will multiply by 10 and 4 respectively the projected and space number densities of objects in the Southern sky. These two surveys should thus provide considerably more accurate estimates of the bulk flow, Omega_matter^{0.6}/bias, Omega_matter itself, and the primordial density fluctuation spectrum.