Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections
We report the PACS-100um/160um detections of a sample of 42
GALEX-selected and FIR-detected Lyman break galaxies (LBGs) at z ~ 1
located in the COSMOS field and analyze their ultra-violet (UV) to
far-infrared (FIR) properties. The detection of these LBGs in the FIR
indicates that they have a dust content high enough so that its emission
can be directly detected. According to a spectral energy distribution
(SED) fitting with stellar population templates to their UV-to-near-IR
observed photometry, PACS-detected LBGs tend to be bigger, more massive,
dustier, redder in the UV continuum, and UV-brighter than
PACS-undetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disk-like
galaxies and are located over the green-valley and red sequence of the
color-magnitude diagram of galaxies at their redshift. By using their UV
and IR emission, we find that PACS-detected LBGs tend to be less dusty
and have slightly higher total star-formation rates (SFRs) than other
PACS-detected UV-selected galaxies within their same redshift range. As
a consequence of the selection effect due to the depth of the FIR
observations employed, all our PACS-detected LBGs are LIRGs. However,
none of them are in the ULIRG regime, where the FIR observations are
complete. The finding of ULIRGs-LBGs at higher redshifts suggests an
evolution of the FIR emission of LBGs with cosmic time. In an
IRX-$\beta$ diagram, PACS-detected LBGs at z ~ 1 tend to be located
around the relation for local starburst similarly to other UV-selected
PACS-detected galaxies at their same redshift. Consequently, the
dust-correction factors obtained with their UV continuum slope allow to
determine their total SFR, unlike at higher redshifts. However, the dust
attenuation derived from UV to NIR SED fitting overestimates the total
SFR for most of our PACS-detected LBGs in age-dependent way: the
overestimation factor is higher in younger galaxies.