IRAC Imaging of Lockman Hole

IRAC imaging of a 4 . ′ 7 × 4 . ′ 7 area in the Lockman Hole detected over 400 galaxies in the IRAC 3.6 µ m and 4.5 µ m bands, 120 in the 5.8 µ m band, and 80 in the 8.0 µ m 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 6 of the 7 SCUBA sources and all 9 XMM 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. reports the results of a SST survey carried out during the SST In-Orbit-Checkout (IOC) period. Observations were taken as one of the Early Release Observations to demonstrate the sensitivity of Spitzer and its capability of detecting galaxies at high redshifts. Lockman Hole field. results observations field. optical/NIR Of seven sources in the survey area, IRAC detected six and 4.5 µ m bands and four in the 5.8 and 8.0 µ m bands. IRAC also detected mid-infrared counterparts of all 9 XMM sources. Analysis of the Spitzer counterparts of the