FIR-detected Lyman break galaxies at z ~ 3: Dust attenuation and dust correction factors at high redshift

Lyman break galaxies (LBGs) represent one of the kinds of star-forming
galaxies that are found in the high-redshift universe. The detection of
LBGs in the FIR domain can provide very important clues on their dust
attenuation and total SFR, allowing a more detailed study than those
performed so far. In this work we explore the FIR emission of a sample
of 16 LBGs at z ~ 3 in the GOODS-North and GOODS-South fields that are
individually detected in PACS-100um or PACS-160um. These detections
demonstrate the possibility of measuring the dust emission of LBGs at
high redshift. We find that PACS-detected LBGs at z ~ 3 are highly
obscured galaxies which belong to the Ultra luminous IR galaxies or
Hyper luminous IR galaxies class. Their total SFR cannot be recovered
with the dust attenuation factors obtained from their UV continuum slope
or their SED-derived dust attenuation employing Bruzual & Charlot
(2003) templates. Both methods underestimate the results for most of the
galaxies. Comparing with a sample of PACS-detected LBGs at z ~ 1 we find
evidences that the FIR emission of LBGs might have changed with redshift
in the sense that the dustiest LBGs found at z ~ 3 have more prominent
FIR emission, are dustier for a given UV slope, and have higher SFR for
a given stellar mass than the dustiest LBGs found at z ~ 1.