ALMA SPECTROSCOPIC SURVEY in the HUBBLE ULTRA DEEP FIELD: CO LUMINOSITY FUNCTIONS and the EVOLUTION of the COSMIC DENSITY of MOLECULAR GAS

Roberto Decarli, Fabian Walter, Manuel Aravena, Chris Carilli, Rychard Bouwens, Elisabete Da Cunha, Emanuele Daddi, R. J. Ivison, Gergö Popping, Dominik Riechers, Ian R. Smail, Mark Swinbank, Axel Weiss, Timo Anguita, Roberto J. Assef, Franz E. Bauer, Eric F. Bell, Frank Bertoldi, Scott Chapman, Luis ColinaPaulo C. Cortes, Pierre Cox, Mark Dickinson, David Elbaz, Jorge Gónzalez-López, Edo Ibar, Leopoldo Infante, Jacqueline Hodge, Alex Karim, Olivier Le Fevre, Benjamin Magnelli, Roberto Neri, Pascal Oesch, Kazuaki Ota, Hans Walter Rix, Mark Sargent, Kartik Sheth, Arjen Van Der Wel, Paul Van Der Werf, Jeff Wagg

Research output: Contribution to journalArticlepeer-review

76 Citations (Scopus)

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).

Original languageEnglish
Article number69
JournalAstrophysical Journal
Volume833
Issue number1
DOIs
Publication statusPublished - 10 Dec 2016

Keywords

  • galaxies: ISM
  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift
  • surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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