@article{ecfaff0cf58846fbbe29c185fb073167,
title = "ALMA SPECTROSCOPIC SURVEY in the HUBBLE ULTRA DEEP FIELD: CO LUMINOSITY FUNCTIONS and the EVOLUTION of the COSMIC DENSITY of MOLECULAR GAS",
abstract = "In this paper we use ASPECS, the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field in band 3 and band 6, to place blind constraints on the CO luminosity function and the evolution of the cosmic molecular gas density as a function of redshift up to z ∼ 4.5. This study is based on galaxies that have been selected solely through their CO emission and not through any other property. In all of the redshift bins the ASPECS measurements reach the predicted {"}knee{"} of the CO luminosity function (around 5 ×109 K km s-1 pc2). We find clear evidence of an evolution in the CO luminosity function with respect to z ∼ 0, with more CO-luminous galaxies present at z ∼ 2. The observed galaxies at z ∼ 2 also appear more gas-rich than predicted by recent semi-analytical models. The comoving cosmic molecular gas density within galaxies as a function of redshift shows a drop by a factor of 3-10 from z ∼ 2 to z ∼ 0 (with significant error bars), and possibly a decline at z > 3. This trend is similar to the observed evolution of the cosmic star formation rate density. The latter therefore appears to be at least partly driven by the increased availability of molecular gas reservoirs at the peak of cosmic star formation (z ∼ 2).",
keywords = "galaxies: ISM, galaxies: evolution, galaxies: formation, galaxies: high-redshift, surveys",
author = "Roberto Decarli and Fabian Walter and Manuel Aravena and Chris Carilli and Rychard Bouwens and {Da Cunha}, Elisabete and Emanuele Daddi and Ivison, {R. J.} and Gerg{\"o} Popping and Dominik Riechers and Smail, {Ian R.} and Mark Swinbank and Axel Weiss and Timo Anguita and Assef, {Roberto J.} and Bauer, {Franz E.} and Bell, {Eric F.} and Frank Bertoldi and Scott Chapman and Luis Colina and Cortes, {Paulo C.} and Pierre Cox and Mark Dickinson and David Elbaz and Jorge G{\'o}nzalez-L{\'o}pez and Edo Ibar and Leopoldo Infante and Jacqueline Hodge and Alex Karim and Fevre, {Olivier Le} and Benjamin Magnelli and Roberto Neri and Pascal Oesch and Kazuaki Ota and Rix, {Hans Walter} and Mark Sargent and Kartik Sheth and {Van Der Wel}, Arjen and {Van Der Werf}, Paul and Jeff Wagg",
note = "Funding Information: We thank the anonymous referee for excellent feedback that improved the quality of the paper. F.W., I.R.S., and R.J.I. acknowledge support through ERC grants COSMIC-DAWN, DUSTYGAL, and COSMICISM, respectively. M.A. acknowledges partial support from FONDECYT through grant 1140099. D.R. acknowledges support from the National Science Foundation under grant number AST-1614213 to Cornell University. F.E.B. and L.I. acknowledge Conicyt grants Basal-CATA PFB-06/2007 and Anilo ACT1417. Publisher Copyright: {\textcopyright} 2016. The American Astronomical Society. All rights reserved.",
year = "2016",
month = dec,
day = "10",
doi = "10.3847/1538-4357/833/1/69",
language = "English",
volume = "833",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "American Astronomical Society",
number = "1",
}