1302.2327 (I. Oteo et al.)

Lyman break and UV-selected galaxies at $z \sim 1$ I. Stellar populations from ALHAMBRA survey    [PDF]

I. Oteo, Á. Bongiovanni, J. Cepa, A. M. Pérez-García, A. Ederoclite, M. Sánchez-Portal, I. Pintos-Castro, R. Pérez-Martínez, J. A. L. Aguerri, E. J. Alfaro, T. Aparicio-Villegas, N. Benítez, T. Broadhurst, J. Cabrera-Caño, F. J. Castander, M. Cerviño, D. Cristobal-Hornillos, A. Fernandez-Soto, R. M. Gonzalez-Delgado, C. Husillos, L. Infante, V. J. Martínez, I. Márquez, J. Masegosa, I. Matute, M. Moles, A. Molino, A. del Olmo, J. Perea, F. Prada, J. M. Quintana

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.

View original: http://arxiv.org/abs/1302.2327