The gas mass reservoir of quiescent galaxies at cosmic noon

¹ Cosmic Dawn Center (DAWN), Rådmandsgade 62, 2200 København, Denmark
e-mail: dblse@space.dtu.dk
² DTU Space, Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark
³ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
⁴ Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark
⁵ Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso, Chile
⁶ Department of Astronomy, The University of Texas at Austin, 2515 Speedway Blvd Stop C1400, Austin, TX 78712, USA
⁷ Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA
⁸ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Munchen, Germany
⁹ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
¹⁰ Max-Planck-Institut für Astronomie, K’onigstuhl 17, 69117 Heidelberg, Germany
¹¹ Istituto Nazionale di Astrofisica (INAF), Vicolo dell’Osservatorio 5, 35122 Padova, Italy
¹² Department of Astronomy, University of Geneva, Chemin Pegasi 51, 1290 Versoix, Switzerland
¹³ Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, PR China
¹⁴ Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstraße 1, 85748 Garching, Germany
¹⁵ Kapteyn Astronomical Institute, University of Groningen, PO Box 800 9700 AV Groningen, The Netherlands

Received: 23 January 2023
Accepted: 16 March 2023

Abstract

We present a 1.1 mm stacking analysis of moderately massive (log(M_*/M_⊙) = 10.7 ± 0.2) quiescent galaxies (QGs) at ⟨z⟩∼1.5, searching for cold dust continuum emission, which serves as an excellent tracer of dust and gas mass. Using both the recent GOODS-ALMA survey, as well as the full suite of ALMA Band-6 ancillary data in the GOODS-S field, we report the tentative detection of a dust continuum equivalent of the dust mass log(M_dust/M_⊙) = 7.47 ± 0.13 and gas mass log(M_gas/M_⊙) = 9.42 ± 0.14. The emerging gas fraction is f_gas = 5.3 ± 1.8%, consistent with the results of previous stacking analyses based on lower resolution sub(mm) observations. Our results support the scenario where high-z QGs exhibit a larger f_gas value by one order of magnitude compared to their local counterparts and have experienced quenching with a non-negligible gas reservoir in their interstellar medium, namely, with gas retention. Our subsequent analysis yields an anti-correlation between the f_gas and the stellar mass of QGs, especially in the high-mass end where galaxies reside in the most massive halos. The f_gas − M_* anti-correlation promotes the selection bias as a possible solution to the tension between the stacking results pointing towards gas retention in high-z QGs of moderate M_* and studies of individual targets that favour a fully depleted ISM in massive (log(M_*/M_⊙) > 11.2) high-z QGs.