T. M. A. Webb et al. 2009 ApJ 692 1561 doi:10.1088/0004-637X/692/2/1561
T. M. A. Webb1, T. Yamada2, J.-S. Huang3, M. L. N Ashby3, Y. Matsuda4,5, E. Egami6, M. Gonzalez1 and T. Hayashimo7
Show affiliationsWe present the results of a Spitzer IRAC and MIPS 24 μm study of extended Lyman-α clouds (or Lyman-α Blobs, LABs) within the SSA22 filamentary structure at z = 3.09. We detect 6/26 LABs in all IRAC filters, four of which are also detected at 24 μm, and find good correspondence with the 850 μm measurements of Geach et al. An analysis of the rest-frame ultraviolet, optical, near- and mid-infrared colors reveals that these six systems exhibit signs of nuclear activity (active galactic nucleus (AGN)) and/or extreme star formation. Notably, they have properties that bridge galaxies dominated by star formation (Lyman-break galaxies (LBGs)) and those with AGNs (LBGs classified as QSOs). The LAB systems not detected in all four IRAC bands, on the other hand, are, as a group, consistent with pure star-forming systems, similar to the majority of the LBGs within the filament. These results indicate that the galaxies within LABs do not comprise a homogeneous population, though they are also consistent with scenarios in which the gas halos are ionized through a common mechanism such as galaxy-scale winds driven by the galaxies within them, or gravitational heating of the collapsing cloud itself.
dust, extinction; galaxies: active; galaxies: formation; galaxies: high-redshift; galaxies: starburst; infrared: galaxies
Issue 2 (2009 February 20)
Received 2008 August 1, accepted for publication 2008 October 15
Published 2009 February 24
T. M. A. Webb et al. 2009 ApJ 692 1561
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