Infrared array camera (IRAC) imaging of the Lockman Hole

IRAC imaging of a 4.7 x 4.'7 area in the Lockman Hole detected over 400 galaxies in the IRAC 3.6 and 4.5 mum bands, 120 in the 5.8 mum band, and 80 in the 8.0 mum band in 30 minutes of observing time. Color-color diagrams suggest that about half of these galaxies are at redshifts 0.6 < z < 1.3 with about a quarter at higher redshifts ( z > 1.3). We also detect IRAC counterparts for six of the seven SCUBA sources and all nine XMM-Newton sources in this area. The detection of the counterparts of the SCUBA sources and galaxies at z > 1: 3 demonstrates the ability of IRAC to probe the universe at very high redshifts.