Far-infrared-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 far-infrared (FIR) domain can provide very important clues
on their dust attenuation and total star-formation rate (SFR), allowing
a more detailed study than has been 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-100 μm or PACS-160 μm. 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 or hyper-luminous IR galaxy 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 evidence 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.

Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.Appendix A is available in electronic form at <A