GOODS-ALMA 2.0: Starbursts in the main sequence reveal compact star formation regulating galaxy evolution prequenching

¹ AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France
e-mail: carlos.gomezguijarro@cea.fr
² School of Astronomy and Space Science, Nanjing University, Nanjing 210093, PR China
³ Cosmic Dawn Center (DAWN), Denmark
⁴ Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen N, Denmark
⁵ DTU-Space, Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark
⁶ Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK
⁷ International Space Science Institute (ISSI), Hallerstrasse 6, 3012 Bern, Switzerland
⁸ Community Science and Data Center/NSF’s NOIRLab., 950 N. Cherry Ave., Tucson, AZ 85719, USA
⁹ Aix Marseille Université, CNRS, LAM, Laboratoire d’Astrophysique de Marseille, Marseille, France
¹⁰ Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK
¹¹ Astronomy Department, University of Massachusetts, Amherst, MA 01003, USA
¹² Departamento de Astronomía, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Concepción, Chile
¹³ Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
¹⁴ Department of Physics, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand
¹⁵ National Astronomical Research Institute of Thailand (Public Organization), Don Kaeo, Mae Rim, Chiang Mai 50180, Thailand
¹⁶ Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
¹⁷ Department of Physics, Anhui Normal University, Wuhu, Anhui 241000, PR China
¹⁸ Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, PR China
¹⁹ Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham DH1 3LE, UK
²⁰ Infrared Processing and Analysis Center, MS314-6, California Institute of Technology, Pasadena, CA 91125, USA
²¹ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
²² Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA
²³ National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
²⁴ SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
²⁵ School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623, USA
²⁶ Institute of Astronomy & Astrophysics, Academia Sinica, Taipei 10617, Taiwan
²⁷ Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
²⁸ Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
²⁹ Astronomy Unit, Department of Physics, University of Trieste, Via Tiepolo 11, 34131 Trieste, Italy
³⁰ Fakultät für Physik der Ludwig-Maximilians-Universität, 81679 München, Germany
³¹ Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USA
³² George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USA
³³ Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile

Received: 1 October 2021
Accepted: 16 December 2021

Abstract

Compact star formation appears to be generally common in dusty star-forming galaxies (SFGs). However, its role in the framework set by the scaling relations in galaxy evolution remains to be understood. In this work we follow up on the galaxy sample from the GOODS-ALMA 2.0 survey, an ALMA blind survey at 1.1 mm covering a continuous area of 72.42 arcmin² using two array configurations. We derived physical properties, such as star formation rates, gas fractions, depletion timescales, and dust temperatures for the galaxy sample built from the survey. There exists a subset of galaxies that exhibit starburst-like short depletion timescales, but they are located within the scatter of the so-called main sequence of SFGs. These are dubbed starbursts in the main sequence and display the most compact star formation and they are characterized by the shortest depletion timescales, lowest gas fractions, and highest dust temperatures of the galaxy sample, compared to typical SFGs at the same stellar mass and redshift. They are also very massive, accounting for ∼60% of the most massive galaxies in the sample (log(M_*/M_⊙) > 11.0). We find trends between the areas of the ongoing star formation regions and the derived physical properties for the sample, unveiling the role of compact star formation as a physical driver of these properties. Starbursts in the main sequence appear to be the extreme cases of these trends. We discuss possible scenarios of galaxy evolution to explain the results drawn from our galaxy sample. Our findings suggest that the star formation rate is sustained in SFGs by gas and star formation compression, keeping them within the main sequence even when their gas fractions are low and they are presumably on the way to quiescence.