University of Sussex
Browse

File(s) not publicly available

Star formation & folecular gas over cosmic time

chapter
posted on 2023-06-08, 17:23 authored by E Daddi, Mark Sargent, M Béthermin, G Magdis
Recent observations have revealed the existence of a ‘main sequence’ of star-forming galaxies out to high redshift. While the majority of star-forming galaxies are observed to be close to this relation between star formation rate (SFR) and stellar mass, a smaller subset of the population – so-called ‘starbursts’ – displays specific star-formation rates and star-formation efficiencies that exceed those of normal (main-sequence) galaxies by up to an order of magnitude. A large degree of homogeneity and similarity has been observed for the properties of the population of normal galaxies across a broad redshift range, including a narrow correlation between their CO luminosity (hence gas content) and IR luminosity and an almost invariable IR SED getting warmer with redshift, while starburst galaxies display systematically different properties. This can be used to devise a simple description of the evolution of the star-forming galaxy population since z ~ 2 and, with a higher degree of uncertainty, even further back in time, in a scheme that we dub two star formation mode framework (2-SFM). We show how this can successfully reproduce the shape of the IR luminosity function of galaxies as a function of redshifts, and the IR number counts. Furthermore, we can link the cosmic evolution of the sSFR of main-sequence galaxies to the evolution of the molecular fuel reservoir and to derive estimates of the molecular gas mass functions of star-forming galaxies that are based on their empirically measured gas properties rather than simulations or semi-analytical modelling. We also infer the evolution of the cosmic abundance of molecular gas and briefly discuss its expected observational signature by molecular line emission, the CO luminosity function.

History

Publication status

  • Published

Journal

Proceedings of the International Astronomical Union

ISSN

1743-9213

Publisher

Cambridge Journals Online

Issue

S295

Volume

8

Page range

64-73

Book title

Proceedings of the International Astronomical Union

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • No

Peer reviewed?

  • No

Legacy Posted Date

2014-05-21

Usage metrics

    University of Sussex (Publications)

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC