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Evolution of the dust emission of massive galaxies up to z = 4 and constraints on their dominant mode of star formation

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posted on 2023-06-08, 19:27 authored by Matthieu Béthermin, Emanuele Daddi, Georgios Magdis, Claudia Lagos, Mark Sargent, Marcus Albrecht, Hervé Aussel, Frank Bertoldi, Véronique Buat, Maud Galametz, Sébastien Heinis, Olivier Ilbert, Alexander Karim, Anton Koekemoer, Cedric Lacey, Emeric Le Floc'h, Felipe Navarrete, Maurilio Pannella, Corentin Schreiber, Vernesa Smolcic, Myrto Symeonidis, Marco Viero
We aim to measure the average dust and molecular gas content of massive star-forming galaxies (>3 × 1010M?) up to z = 4 in the COSMOS field to determine if the intense star formation observed at high redshift is induced by major mergers or is caused by large gas reservoirs. Firstly, we measured the evolution of the average spectral energy distributions as a function of redshift using a stacking analysis of Spitzer, Herschel, LABOCA, and AzTEC data for two samples of galaxies: normal star-forming objects and strong starbursts, as defined by their distance to the main sequence. We found that the mean intensity of the radiation field ? U ? heating the dust (strongly correlated with dust temperature) increases with increasing redshift up to z = 4 in main-sequence galaxies. We can reproduce this evolution with simple models that account for the decrease in the gas metallicity with redshift. No evolution of ? U ? with redshift is found in strong starbursts. We then deduced the evolution of the molecular gas fraction (defined here as Mmol/ (Mmol + M?)) with redshift and found a similar, steeply increasing trend for both samples. At z ~ 4, this fraction reaches ~60%. The average position of the main-sequence galaxies is on the locus of the local, normal star-forming disks in the integrated Schmidt-Kennicutt diagram (star formation rate versus mass of molecular gas), suggesting that the bulk of the star formation up to z = 4 is dominated by secular processes.

History

Publication status

  • Published

File Version

  • Accepted version

Journal

Astronomy and Astrophysics

ISSN

0004-6361

Publisher

EDP Sciences

Volume

573

Article number

A113

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2015-01-08

First Open Access (FOA) Date

2015-01-08

First Compliant Deposit (FCD) Date

2015-01-08

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