The ALPINE-ALMA [CII] survey: Molecular gas budget in the early Universe as traced by [CII]
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The ALPINE-ALMA [CII] survey : Molecular gas budget in the early Universe as traced by [CII]. / Dessauges-Zavadsky, M.; Ginolfi, M.; Pozzi, F.; Bethermin, M.; Le Fevre, O.; Fujimoto, S.; Silverman, J. D.; Jones, G. C.; Vallini, L.; Schaerer, D.; Faisst, A. L.; Khusanova, Y.; Fudamoto, Y.; Cassata, P.; Loiacono, F.; Capak, P. L.; Yan, L.; Amorin, R.; Bardelli, S.; Boquien, M.; Cimatti, A.; Gruppioni, C.; Hathi, N. P.; Ibar, E.; Koekemoer, A. M.; Lemaux, B. C.; Narayanan, D.; Oesch, P. A.; Rodighiero, G.; Romano, M.; Talia, M.; Toft, S.; Vergani, D.; Zamorani, G.; Zucca, E.
In: Astronomy & Astrophysics, Vol. 643, A5, 27.10.2020.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The ALPINE-ALMA [CII] survey
T2 - Molecular gas budget in the early Universe as traced by [CII]
AU - Dessauges-Zavadsky, M.
AU - Ginolfi, M.
AU - Pozzi, F.
AU - Bethermin, M.
AU - Le Fevre, O.
AU - Fujimoto, S.
AU - Silverman, J. D.
AU - Jones, G. C.
AU - Vallini, L.
AU - Schaerer, D.
AU - Faisst, A. L.
AU - Khusanova, Y.
AU - Fudamoto, Y.
AU - Cassata, P.
AU - Loiacono, F.
AU - Capak, P. L.
AU - Yan, L.
AU - Amorin, R.
AU - Bardelli, S.
AU - Boquien, M.
AU - Cimatti, A.
AU - Gruppioni, C.
AU - Hathi, N. P.
AU - Ibar, E.
AU - Koekemoer, A. M.
AU - Lemaux, B. C.
AU - Narayanan, D.
AU - Oesch, P. A.
AU - Rodighiero, G.
AU - Romano, M.
AU - Talia, M.
AU - Toft, S.
AU - Vergani, D.
AU - Zamorani, G.
AU - Zucca, E.
PY - 2020/10/27
Y1 - 2020/10/27
N2 - The molecular gas content of normal galaxies at z> 4 is poorly constrained because the commonly used molecular gas tracers become hard to detect at these high redshifts. We use the [CII] 158 mu m luminosity, which was recently proposed as a molecular gas tracer, to estimate the molecular gas content in a large sample of main sequence star-forming galaxies at z=4.4-5.9, with a median stellar mass of 10(9.7) M-circle dot, drawn from the ALMA Large Program to INvestigate [CII] at Early times survey. The agreement between the molecular gas masses derived from [CII] luminosities, dynamical masses, and rest-frame 850 mu m luminosities extrapolated from the rest-frame 158 mu m continuum supports [CII] as a reliable tracer of molecular gas in our sample. We find a continuous decline of the molecular gas depletion timescale from z=0 to z=5.9, which reaches a mean value of (4.6 +/- 0.8) x 10(8) yr at z similar to 5.5, only a factor of between two and three shorter than in present-day galaxies. This suggests a mild enhancement of the star formation efficiency toward high redshifts. Our estimates also show that the previously reported rise in the molecular gas fraction flattens off above z similar to 3.7 to achieve a mean value of 63%+/- 3% over z=4.4-5.9. This redshift evolution of the gas fraction is in line with that of the specific star formation rate. We use multi-epoch abundance-matching to follow the gas fraction evolution across cosmic time of progenitors of z=0 Milky Way-like galaxies in similar to 10(13) M-circle dot halos and of more massive z=0 galaxies in similar to 10(14) M-circle dot halos. Interestingly, the former progenitors show a monotonic increase of the gas fraction with redshift, while the latter show a steep rise from z=0 to z similar to 2 followed by a constant gas fraction from z similar to 2 to z=5.9. We discuss three possible effects, namely outflows, a pause in gas supply, and over-efficient star formation, which may jointly contribute to the gas fraction plateau of the latter massive galaxies.
AB - The molecular gas content of normal galaxies at z> 4 is poorly constrained because the commonly used molecular gas tracers become hard to detect at these high redshifts. We use the [CII] 158 mu m luminosity, which was recently proposed as a molecular gas tracer, to estimate the molecular gas content in a large sample of main sequence star-forming galaxies at z=4.4-5.9, with a median stellar mass of 10(9.7) M-circle dot, drawn from the ALMA Large Program to INvestigate [CII] at Early times survey. The agreement between the molecular gas masses derived from [CII] luminosities, dynamical masses, and rest-frame 850 mu m luminosities extrapolated from the rest-frame 158 mu m continuum supports [CII] as a reliable tracer of molecular gas in our sample. We find a continuous decline of the molecular gas depletion timescale from z=0 to z=5.9, which reaches a mean value of (4.6 +/- 0.8) x 10(8) yr at z similar to 5.5, only a factor of between two and three shorter than in present-day galaxies. This suggests a mild enhancement of the star formation efficiency toward high redshifts. Our estimates also show that the previously reported rise in the molecular gas fraction flattens off above z similar to 3.7 to achieve a mean value of 63%+/- 3% over z=4.4-5.9. This redshift evolution of the gas fraction is in line with that of the specific star formation rate. We use multi-epoch abundance-matching to follow the gas fraction evolution across cosmic time of progenitors of z=0 Milky Way-like galaxies in similar to 10(13) M-circle dot halos and of more massive z=0 galaxies in similar to 10(14) M-circle dot halos. Interestingly, the former progenitors show a monotonic increase of the gas fraction with redshift, while the latter show a steep rise from z=0 to z similar to 2 followed by a constant gas fraction from z similar to 2 to z=5.9. We discuss three possible effects, namely outflows, a pause in gas supply, and over-efficient star formation, which may jointly contribute to the gas fraction plateau of the latter massive galaxies.
KW - galaxies: evolution
KW - galaxies: high-redshift
KW - galaxies: ISM
KW - ISM: molecules
KW - STAR-FORMING GALAXIES
KW - MASS-METALLICITY RELATION
KW - C-II
KW - MAIN-SEQUENCE
KW - SCALING RELATIONS
KW - CONVERSION FACTOR
KW - LEGACY SURVEY
KW - EVOLUTION
KW - MODEL
KW - DUST
U2 - 10.1051/0004-6361/202038231
DO - 10.1051/0004-6361/202038231
M3 - Journal article
VL - 643
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
SN - 0004-6361
M1 - A5
ER -
ID: 252147508