A MULTIPLY IMAGED LUMINOUS INFRARED GALAXY BEHIND THE BULLET CLUSTER (1E0657-56)

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Abstract
We present evidence for a Spitzer-selected luminous infrared galaxy (LIRG) behind the Bullet Cluster (1E0657-56). The galaxy, originally identified as a multiply imaged source using Infrared Array Camera (IRAC) photometry, has a spectral energy distribution consistent with a highly extincted (AV ~ 3.3), strongly star forming galaxy at z = 2.7. Using our strong gravitational lensing model presented in a previous paper, we find that the magnifications are |μ| ≈ 10-50 for the three images of the galaxy. The brightest and faintest images differ by a factor of 3.2 in magnification. The implied infrared luminosity is consistent with the galaxy being a LIRG, with a stellar mass of M * ~ 2 × 1010 M ☉ and a star formation rate (SFR) of ~90 M ☉ yr–1. With lensed fluxes at 24 μm of 0.58 mJy and 0.39 mJy in the two brightest images, this galaxy presents a unique opportunity for detailed study of an obscured starburst with a SFR comparable to that of L* galaxies at z > 2.