We present PHIBSS, the IRAM Plateau de Bure high-z blue sequence CO 3-2 survey of the molecular gas properties in normal star forming galaxies (SFGs) near the cosmic star formation peak. PHIBSS provides 52 CO detections in two redshift slices at z~1.2 and 2.2, with log(M*(M_solar))>10.4 and log(SFR(M_solar/yr))>1.5. Including a correction for the incomplete coverage of the M*-SFR plane, we infer average gas fractions of ~0.33 at z~1.2 and ~0.47 at z~2.2. Gas fractions drop with stellar mass, in agreement with cosmological simulations including strong star formation feedback. Most of the z~1-3 SFGs are rotationally supported turbulent disks. The sizes of CO and UV/optical emission are comparable. The molecular gas - star formation relation for the z=1-3 SFGs is near-linear, with a ~0.7 Gyrs gas depletion timescale; changes in depletion time are only a secondary effect. Since this timescale is much less than the Hubble time in all SFGs between z~0 and 2, fresh gas must be supplied with a fairly high duty cycle over several billion years. At given z and M*, gas fractions correlate strongly with the specific star formation rate. The variation of specific star formation rate between z~0 and 3 is mainly controlled by the fraction of baryonic mass that resides in cold gas.
@article{arxiv.1211.5743,
title = {PHIBSS: molecular gas content and scaling relations in z~1-3 normal star forming galaxies},
author = {L. J. Tacconi and R. Neri and R. Genzel and F. Combes and A. Bolatto and M. C. Cooper and S. Wuyts and F. Bournaud and A. Burkert and J. Comerford and P. Cox and M. Davi and N. M. Förster Schreiber and S. García-Burillo and J. Gracia-Carpio and D. Lutz and T. Naab and S. Newman and A. Omont and A. Saintonge and K. Shapiro Griffin and A. Shapley and A. Sternberg and B. Weiner},
journal= {arXiv preprint arXiv:1211.5743},
year = {2015}
}
Comments
Submitted to the Astrophysical Journal; 14 figures