Ultraviolet-bright, high-redshift ULIRGS

Abstract

We present Spitzer Space Telescope observations of the z=2.38 Lyα-emitter over-densityassociated with galaxy cluster J2143-4423, the largest known structure (110 Mpc)above z=2.We imaged 22 of the 37 known Lyα-emitters within the filament-like structure,using the MIPS 24μ/m band. We detected 6 of the Lyα-emitters, including 3 of the 4 clouds of extended (>50kpc) Lyα emission, also known as Lyα Blobs. Conversion from rest-wavelength 7μ to total far-infrared luminosityusing locally derived correlations suggests all the detected sources are in the class of ULIRGs, with some reaching Hyper-LIRG energies. Lyα blobs frequently show evidence for interaction, either in HST imaging,or the proximity of multiple MIPS sources within the Lyα cloud. This connection suggests that interaction or even mergers may be related to the production of Lyα blobs. A connection to mergersdoes not in itself help explain the origin of the Lyα blobs, as most of the suggested mechanisms for creating Lyα blobs (starbursts, AGN, cooling flows) could alsobe associated with galaxy interactions. © 2008 Springer-Verlag Berlin Heidelberg.