Lyman break and UV-selected galaxies at $z \sim 1$ I. Stellar populations from ALHAMBRA survey
We take advantage of the exceptional photometric coverage provided by
the combination of GALEX data in the UV and the ALHAMBRA survey in the
optical and near-IR to analyze the physical properties of a sample of
1225 GALEX-selected Lyman break galaxies (LBGs) at $0.8 \lesssim z
\lesssim 1.2$ located in the COSMOS field. This is the largest sample of
LBGs studied at that redshift range so far. According to a spectral
energy distribution fitting with synthetic stellar population templates,
we find that LBGs at $z \sim 1$ are mostly young galaxies with a median
value of 341 Myr and have intermediate dust attenuation, $< E_s
(B-V)> \sim 0.20$. Due to their selection criterion they are
UV-bright galaxies and have high dust-corrected total SFRs, with a
median value of 46.4 $M_\odot {\rm yr}^{-1}$. The median value of the
stellar mass of the LBGs in the sample is $\log{M_*/M_\odot} = 9.74$. We
obtain that the dust-corrected total SFR of LBGs increases with stellar
mass and the specific SFR is lower for more massive galaxies (downsizing
scenario). Only 2% of the galaxies selected through the Lyman break
criterion have an AGN nature. LBGs are mostly located over the blue
cloud of the color-magnitude diagram of galaxies at their redshift, with
only the oldest and/or the dustiest deviating towards the green valley
and red sequence. Morphologically, 69% of LBGs are disk-like galaxies,
with a fraction of interacting, compact, or irregular systems being much
lower, below 12%. LBGs have a median effective radius of 2.48 kpc and
bigger galaxies have higher total SFRs and stellar masses. Comparing to
their high-redshift analogues, we find that LBGs at lower redshifts are
bigger, redder in the UV continuum, and the presence of older stellar
populations in their SEDs is more remarkable, although there is no
significant difference in the distributions of stellar mass or dust
attenuation.