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ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: CO Luminosity Functions and the Evolution of the Cosmic Density of Molecular Gas

Decarli, R.; Walter, F.; Aravena, M.; Carilli, C.; Bouwens, R.; da Cunha, E.; Daddi, E.; Ivison, R.J.; Popping, G.; Riechers, D.; Smail, I.R.; Swinbank, M.; Weiss, A.; Anguita, T.; Assef, R.J.; Bauer, F.E.; Bell, E.F.; Bertoldi, F.; Chapman, S.; Colina, L.; Cortes, P.C.; Cox, P.; Dickinson, M.; Elbaz, D.; Gónzalez-López, J.; Ibar, E.; Infante, L.; Hodge, J.; Karim, A.; Le Fevre, O.; Magnelli, B.; Neri, R.; Oesch, P.; Ota, K.; Rix, H.-W.; Sargent, M.; Sheth, K.; van der Wel, A.; van der Werf, P.; Wagg, J.

ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: CO Luminosity Functions and the Evolution of the Cosmic Density of Molecular Gas Thumbnail


R. Decarli

F. Walter

M. Aravena

C. Carilli

R. Bouwens

E. da Cunha

E. Daddi

R.J. Ivison

G. Popping

D. Riechers

A. Weiss

T. Anguita

R.J. Assef

F.E. Bauer

E.F. Bell

F. Bertoldi

S. Chapman

L. Colina

P.C. Cortes

P. Cox

M. Dickinson

D. Elbaz

J. Gónzalez-López

E. Ibar

L. Infante

J. Hodge

A. Karim

O. Le Fevre

B. Magnelli

R. Neri

P. Oesch

K. Ota

H.-W. Rix

M. Sargent

K. Sheth

A. van der Wel

P. van der Werf

J. Wagg


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).

Journal Article Type Article
Acceptance Date Sep 7, 2016
Online Publication Date Dec 8, 2016
Publication Date Dec 8, 2016
Deposit Date Feb 22, 2017
Publicly Available Date Mar 9, 2017
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 833
Issue 1
Article Number 69
Public URL
Related Public URLs


Published Journal Article (1 Mb)

Copyright Statement
© 2016. The American Astronomical Society. All rights reserved.

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