ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: CO LUMINOSITY FUNCTIONS AND THE EVOLUTION OF THE COSMIC DENSITY OF MOLECULAR GAS

作者：Decarli Roberto; Walter Fabian; Aravena Manuel; Carilli Chris; Bouwens Rychard; Da Cunha Elisabete; Daddi Emanuele; Ivison R J; Popping Gergo; Riechers Dominik; Smail Ian R; Swinbank Mark; Weiss Axel; Anguita Timo; Assef Roberto J; Bauer Franz E; Bell Eric F; Bertoldi Frank; Chapman Scott; Colina Luis; Cortes Paulo C; Cox Pierre; Dickinson Mark; Elbaz David; Gonzalez Lopez Jorge; Ibar Edo; Infante Leopoldo; Hodge Jacqueline; Karim Alex; Le Fevre Olivier

来源：Astrophysical Journal, 2016, 833(1): 69.

DOI：10.3847/1538-4357/833/1/69

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

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 similar to 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 around 5 x 10(9) K km s(-1) pc(2)). We find clear evidence of an evolution in the CO luminosity function with respect to z similar to 0, with more CO-luminous galaxies present at z similar to 2. The observed galaxies at z similar to 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 similar to 2 to z similar to 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 similar to 2).

• 出版日期2016-12-10
• 单位中国地震局