TY - JOUR
T1 - THE ALMA SPECTROSCOPIC SURVEY in the HUBBLE ULTRA DEEP FIELD
T2 - MOLECULAR GAS RESERVOIRS in HIGH-REDSHIFT GALAXIES
AU - Decarli, Roberto
AU - Walter, Fabian
AU - Aravena, Manuel
AU - Carilli, Chris
AU - Bouwens, Rychard
AU - Cunha, Elisabete Da
AU - Daddi, Emanuele
AU - Elbaz, David
AU - Riechers, Dominik
AU - Smail, Ian
AU - Swinbank, Mark
AU - Weiss, Axel
AU - Bacon, Roland
AU - Bauer, Franz
AU - Bell, Eric F.
AU - Bertoldi, Frank
AU - Chapman, Scott
AU - Colina, Luis
AU - Cortes, Paulo C.
AU - Cox, Pierre
AU - Gónzalez-López, Jorge
AU - Inami, Hanae
AU - Ivison, Rob
AU - Hodge, Jacqueline
AU - Karim, Alex
AU - Magnelli, Benjamin
AU - Ota, Kazuaki
AU - Popping, Gergö
AU - Rix, Hans Walter
AU - Sargent, Mark
AU - Wel, Arjen Van Der
AU - Werf, Paul Van Der
N1 - Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/12/10
Y1 - 2016/12/10
N2 - We study the molecular gas properties of high-z galaxies observed in the ALMA Spectroscopic Survey (ASPECS) that targets an ∼1 arcmin2 region in the Hubble Ultra Deep Field (UDF), a blind survey of CO emission (tracing molecular gas) in the 3 and 1 mm bands. Of a total of 1302 galaxies in the field, 56 have spectroscopic redshifts and correspondingly well-defined physical properties. Among these, 11 have infrared luminosities LIR > 1011L⊙, i.e., a detection in CO emission was expected. Out of these, 7 are detected at various significance in CO, and 4 are undetected in CO emission. In the CO-detected sources, we find CO excitation conditions that are lower than those typically found in starburst/sub-mm galaxy/QSO environments. We use the CO luminosities (including limits for non-detections) to derive molecular gas masses. We discuss our findings in the context of previous molecular gas observations at high redshift (star formation law, gas depletion times, gas fractions): the CO-detected galaxies in the UDF tend to reside on the low- envelope of the scatter in the relation, but exceptions exist. For the CO-detected sources, we find an average depletion time of ∼1 Gyr, with significant scatter. The average molecular-to-stellar mass ratio (/M ∗) is consistent with earlier measurements of main-sequence galaxies at these redshifts, and again shows large variations among sources. In some cases, we also measure dust continuum emission. On average, the dust-based estimates of the molecular gas are a factor ∼2-5× smaller than those based on CO. When we account for detections as well as non-detections, we find large diversity in the molecular gas properties of the high-redshift galaxies covered by ASPECS.
AB - We study the molecular gas properties of high-z galaxies observed in the ALMA Spectroscopic Survey (ASPECS) that targets an ∼1 arcmin2 region in the Hubble Ultra Deep Field (UDF), a blind survey of CO emission (tracing molecular gas) in the 3 and 1 mm bands. Of a total of 1302 galaxies in the field, 56 have spectroscopic redshifts and correspondingly well-defined physical properties. Among these, 11 have infrared luminosities LIR > 1011L⊙, i.e., a detection in CO emission was expected. Out of these, 7 are detected at various significance in CO, and 4 are undetected in CO emission. In the CO-detected sources, we find CO excitation conditions that are lower than those typically found in starburst/sub-mm galaxy/QSO environments. We use the CO luminosities (including limits for non-detections) to derive molecular gas masses. We discuss our findings in the context of previous molecular gas observations at high redshift (star formation law, gas depletion times, gas fractions): the CO-detected galaxies in the UDF tend to reside on the low- envelope of the scatter in the relation, but exceptions exist. For the CO-detected sources, we find an average depletion time of ∼1 Gyr, with significant scatter. The average molecular-to-stellar mass ratio (/M ∗) is consistent with earlier measurements of main-sequence galaxies at these redshifts, and again shows large variations among sources. In some cases, we also measure dust continuum emission. On average, the dust-based estimates of the molecular gas are a factor ∼2-5× smaller than those based on CO. When we account for detections as well as non-detections, we find large diversity in the molecular gas properties of the high-redshift galaxies covered by ASPECS.
KW - galaxies: ISM
KW - galaxies: evolution
KW - galaxies: star formation
KW - galaxies: statistics
KW - instrumentation: interferometers
KW - submillimeter: galaxies
UR - http://www.scopus.com/inward/record.url?scp=85006511879&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/833/1/70
DO - 10.3847/1538-4357/833/1/70
M3 - Article
SN - 0004-637X
VL - 833
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 70
ER -