TY - JOUR
T1 - PHIBSS2
T2 - Survey design and z = 0.5 - 0.8 results: Molecular gas reservoirs during the winding-down of star formation
AU - Freundlich, J.
AU - Combes, F.
AU - Tacconi, L. J.
AU - Genzel, R.
AU - Garcia-Burillo, S.
AU - Neri, R.
AU - Contini, T.
AU - Bolatto, A.
AU - Lilly, S.
AU - Salomé, P.
AU - Bicalho, I. C.
AU - Boissier, J.
AU - Boone, F.
AU - Bouché, N.
AU - Bournaud, F.
AU - Burkert, A.
AU - Carollo, M.
AU - Cooper, M. C.
AU - Cox, P.
AU - Feruglio, C.
AU - Förster Schreiber, N. M.
AU - Juneau, S.
AU - Lippa, M.
AU - Lutz, D.
AU - Naab, T.
AU - Renzini, A.
AU - Saintonge, A.
AU - Sternberg, A.
AU - Walter, F.
AU - Weiner, B.
AU - Weiß, A.
AU - Wuyts, S.
N1 - Funding Information:
Acknowledgements. The authors acknowledge the particularly careful reading of the anonymous referee, which greatly contributed to improving this article. J. F. would like to thank Benoît Epinat and Marc Huertas Company for their advice using Galfit, and Avishai Dekel, Sandy Faber, Joel Primack, Sandro Tacchella, Sharon Lapiner and Casey Papovich for interesting discussions and insights. The observations presented here were carried out at the IRAM Plateau de Bure/NOEMA interferometer and we are grateful to the astronomers on duty and telescope operators for the quality of the data. This study makes use of data from AEGIS, a multi-wavelength sky survey conducted with the Chandra, GALEX, Hubble, Keck, CFHT, MMT, Subaru, Palomar, Spitzer, VLA, and other telescopes and supported in part by the NSF, NASA, and the STFC. It is also based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under ESO programme ID 179.A-2005 and on data products produced by TERAPIX and the Cambridge Astronomy Survey Unit on behalf of the UltraVISTA consortium. This study further uses observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Finally, this work was based in part on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA).
Publisher Copyright:
© 2019 ESO.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Following the success of the Plateau de Bure high-z Blue Sequence Survey (PHIBSS), we present the PHIBSS2 legacy program, a survey of the molecular gas properties of star-forming galaxies on and around the star-formation main sequence (MS) at different redshifts using IRAM's NOrthern Extended Millimeter Array (NOEMA). This survey significantly extends the existing sample of star-forming galaxies with CO molecular gas measurements, probing the peak epoch of star formation (z = 1 - 1.6) as well as its building-up (z = 2 - 3) and winding-down (z = 0.5 - 0.8) phases. The targets are drawn from the well-studied GOODS, COSMOS, and AEGIS cosmological deep fields and uniformly sample the MS in the stellar mass (M ∗ ) - star formation rate (SFR) plane with log(M ∗ /M · ) = 10 - 11.8 and SFR = 3.5 - 500 M · yr -1 without morphological selection, thus providing a statistically meaningful census of star-forming galaxies at different epochs. We describe the survey strategy and sample selection before focusing on the results obtained at redshift z = 0.5 - 0.8, where we report 60 CO(2-1) detections out of 61 targets. We determine molecular gas masses between 2 × 10 9 and 5 × 10 10 M · and separately obtain disc sizes and bulge-to-total (B/T) luminosity ratios from HST I-band images. The median molecular gas-to-stellar mass ratio μ gas ∼ = 0.28 ± 0.04, gas fraction f gas ∼ = 0.22 ± 0.02, and depletion time t depl = 0.84 ± 0.07 Gyr as well as their dependence with stellar mass and offset from the MS follow published scaling relations for a much larger sample of galaxies spanning a significantly wider range of redshifts, the cosmic evolution of the SFR being mainly driven by that of the molecular gas fraction. The galaxy-averaged molecular Kennicutt-Schmidt (KS) relation between molecular gas and SFR surface densities is strikingly linear, pointing towards similar star formation timescales within galaxies at any given epoch. In terms of morphology, the molecular gas content, the SFR, the disc stellar mass, and the disc molecular gas fraction do not seem to correlate with B/T and the stellar surface density, which suggests an ongoing supply of fresh molecular gas to compensate for the build-up of the bulge. Our measurements do not yield any significant variation of the depletion time with B/T and hence no strong evidence for morphological quenching within the scatter of the MS.
AB - Following the success of the Plateau de Bure high-z Blue Sequence Survey (PHIBSS), we present the PHIBSS2 legacy program, a survey of the molecular gas properties of star-forming galaxies on and around the star-formation main sequence (MS) at different redshifts using IRAM's NOrthern Extended Millimeter Array (NOEMA). This survey significantly extends the existing sample of star-forming galaxies with CO molecular gas measurements, probing the peak epoch of star formation (z = 1 - 1.6) as well as its building-up (z = 2 - 3) and winding-down (z = 0.5 - 0.8) phases. The targets are drawn from the well-studied GOODS, COSMOS, and AEGIS cosmological deep fields and uniformly sample the MS in the stellar mass (M ∗ ) - star formation rate (SFR) plane with log(M ∗ /M · ) = 10 - 11.8 and SFR = 3.5 - 500 M · yr -1 without morphological selection, thus providing a statistically meaningful census of star-forming galaxies at different epochs. We describe the survey strategy and sample selection before focusing on the results obtained at redshift z = 0.5 - 0.8, where we report 60 CO(2-1) detections out of 61 targets. We determine molecular gas masses between 2 × 10 9 and 5 × 10 10 M · and separately obtain disc sizes and bulge-to-total (B/T) luminosity ratios from HST I-band images. The median molecular gas-to-stellar mass ratio μ gas ∼ = 0.28 ± 0.04, gas fraction f gas ∼ = 0.22 ± 0.02, and depletion time t depl = 0.84 ± 0.07 Gyr as well as their dependence with stellar mass and offset from the MS follow published scaling relations for a much larger sample of galaxies spanning a significantly wider range of redshifts, the cosmic evolution of the SFR being mainly driven by that of the molecular gas fraction. The galaxy-averaged molecular Kennicutt-Schmidt (KS) relation between molecular gas and SFR surface densities is strikingly linear, pointing towards similar star formation timescales within galaxies at any given epoch. In terms of morphology, the molecular gas content, the SFR, the disc stellar mass, and the disc molecular gas fraction do not seem to correlate with B/T and the stellar surface density, which suggests an ongoing supply of fresh molecular gas to compensate for the build-up of the bulge. Our measurements do not yield any significant variation of the depletion time with B/T and hence no strong evidence for morphological quenching within the scatter of the MS.
KW - Galaxies: ISM
KW - Galaxies: evolution
KW - Galaxies: high-redshift
KW - Galaxies: star formation
KW - ISM: molecules
UR - http://www.scopus.com/inward/record.url?scp=85061298474&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85061298474&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201732223
DO - 10.1051/0004-6361/201732223
M3 - Review article
AN - SCOPUS:85061298474
VL - 622
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A105
ER -