1209.1561 (Jaron Kurk et al.)

GMASS ultradeep spectroscopy of galaxies at z~2 - VII. Sample selection and spectroscopy    [PDF]

Jaron Kurk, Andrea Cimatti, Emanuele Daddi, Marco Mignoli, Lucia Pozzetti, Mark Dickinson, Micol Bolzonella, Gianni Zamorani, Paolo Cassata, Giulia Rodighiero, Alberto Franceschini, Alvio Renzini, Piero Rosati, Claire Halliday, Stefano Berta

The populations of both quiescent and actively star-forming galaxies at 11.4, called Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS). To determine redshifts and physical properties, such as metallicity, dust content, dynamical masses, and star formation history, we performed ultra-deep spectroscopy with the red-sensitive optical spectrograph FORS2 at the VLT. Our sample consists of objects, within the CDFS/GOODS area, detected at 4.5 micron, to be sensitive to stellar mass rather than star formation intensity. The spectroscopic targets were selected with a photometric redshift constraint (z>1.4) and magnitude constraints (B(AB)<26, I(AB)<26.5), which should ensure that these are faint, distant, and fairly massive galaxies. We present the sample selection, survey design, observations, data reduction, and spectroscopic redshifts. Up to 30 hours of spectroscopy of 174 spectroscopic targets and 70 additional objects enabled us to determine 210 redshifts, of which 145 are at z>1.4. From the redshifts and photometry, we deduce that the BzK selection criteria are efficient (82%) and suffer low contamination (11%). Several papers based on the GMASS survey show its value for studies of galaxy formation and evolution. We publicly release the redshifts and reduced spectra. In combination with existing and on-going additional observations in CDFS/GOODS, this data set provides a legacy for future studies of distant galaxies.

View original: http://arxiv.org/abs/1209.1561