A³COSMOS: The infrared luminosity function and dust-obscured star formation rate density at 0.5 < z < 6

¹ Istituto Nazionale di Astrofisica (INAF) – Osservatorio di Astrofisica e Scienza dello Spazio (OAS), via Gobetti 101, 40129 Bologna, Italy
e-mail: alberto.traina2@unibo.it
² Dipartimento di Fisica e Astronomia (DIFA), Università di Bologna, via Gobetti 93/2, 40129 Bologna, Italy
³ INAF – Osservatorio Astronomico di Brera 28, 20121, Milano, Italy and Via Bianchi 46, 23807 Merate, Italy
⁴ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
⁵ Dipartimento di Fisica e Astronomia, Università di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
⁶ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
⁷ Université Paris-Saclay, Université Paris-Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
⁸ Max Planck Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁹ Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching bei München, Germany
¹⁰ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
¹¹ SISSA, Via Bonomea 265, 34136 Trieste, Italy
¹² IRA-INAF, Via Gobetti 101, 40129 Bologna, Italy
¹³ Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama-Higashi, Hiroshima 739-8526, Japan
¹⁴ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, 169-8555 Tokyo, Japan
¹⁵ Cosmic Dawn Center (DAWN), Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
¹⁶ DTU-Space, Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark
¹⁷ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
¹⁸ Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK

Received: 30 May 2023
Accepted: 26 September 2023

Abstract

Aims. We leverage the largest available Atacama Large Millimeter/submillimeter Array (ALMA) survey from the archive (A³COSMOS) to study infrared luminosity function and dust-obscured star formation rate density of (sub)millimeter galaxies from z = 0.5 − 6.

Methods. The A³COSMOS survey utilizes all publicly available ALMA data in the COSMOS field and therefore has inhomogeneous coverage in terms of observing wavelength and depth. In order to derive the luminosity functions and star formation rate densities, we applied a newly developed method that corrects the statistics of an inhomogeneously sampled survey of individual pointings to those representing an unbiased blind survey.

Results. We find our sample to mostly consist of massive (M_⋆ ∼ 10¹⁰ − 10¹² M_⊙) IR-bright (L_* ∼ 10¹¹ − 10^13.5 L_⊙) highly star-forming (SFR ∼100 − 1000 M_⊙ yr⁻¹) galaxies. We find an evolutionary trend in the typical density (Φ^*) and luminosity (L^*) of the galaxy population that respectively decreases and increases with redshift. Our infrared luminosity function (LF) is in agreement with previous literature results, and we were able to extend the constraints on the knee and bright end of the LF to high redshift (z > 3) by using the Herschel data. Finally, we obtained the star formation rate density up to z ∼ 6 by integrating the IR LF, finding a broad peak from z ∼ 1 to z ∼ 3 and a decline toward higher redshifts, in agreement with recent IR/millimeter-based studies, within the uncertainties. These results imply the presence of larger quantities of dust than what is expected based on optical/UV studies.