1. PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ~ 1-3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES.
- Author
-
TACCONI, L. J., NERI, R., GENZEL, R., COMBES, F., BOLATTO, A., COOPER, M. C., WUYTS, S., BOURNAUD, F., BURKERT, A., COMERFORD, J., COX, P., DAVIS, M., SCHREIBER, N. M. FÖRSTER, GARCÍA-BURILLO, S., GRACIA-CARPIO, J., LUTZ, D., NAAB, T., NEWMAN, S., OMONT, A., and SAINTONGE, A.
- Subjects
MOLECULAR clouds ,GALACTIC evolution ,GALACTIC redshift ,INTERSTELLAR medium ,STELLAR mass ,STAR formation - Abstract
We present PHIBSS, the IRAM Plateau de Bure high-z blue sequence CO 3-2 survey of the molecular gas properties in massive, main-sequence 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☉ )) ⩾ 10.4 and log(SFR(M☉ /yr)) ⩾ 1.5. Including a correction for the incomplete coverage of the M" -SFR plane, and adopting a "Galactic" value for the CO-H2 conversion factor, 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 Gyr 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 (sSFR). The variation of sSFR between z ~ 0 and 3 is mainly controlled by the fraction of baryonic mass that resides in cold gas. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF