title: A massive, quiescent galaxy at a redshift of 3.717.
abstract: Finding massive galaxies that stopped forming stars in the early Universe presents an observational challenge because their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These surveys have revealed the presence of massive, quiescent early-type galaxies appearing as early as redshift z ≈ 2, an epoch three billion years after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy-formation models, in which they form rapidly at z ≈ 3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, using coarsely sampled photometry. However, these early, massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here we report the spectroscopic confirmation of one such galaxy at redshift z = 3.717, with a stellar mass of 1.7 × 1011solar masses. We derive its age to be nearly half the age of the Universe at this redshift and the absorption line spectrum shows no current star formation. These observations demonstrate that the galaxy must have formed the majority of its stars quickly, within the first billion years of cosmic history in a short, extreme starburst. This ancestral starburst appears similar to those being found by submillimetre-wavelength surveys. The early formation of such massive systems implies that our picture of early galaxy assembly requires substantial revision.
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia.
authors.forename: Karl
authors.initials: K
authors.lastname: Glazebrook
authors.affiliation: Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands.
authors.forename: Corentin
authors.initials: C
authors.lastname: Schreiber
authors.affiliation: Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands.
authors.forename: Ivo
authors.initials: I
authors.lastname: Labbé
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia.
authors.forename: Themiya
authors.initials: T
authors.lastname: Nanayakkara
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia.
authors.forename: Glenn G
authors.initials: GG
authors.lastname: Kacprzak
authors.affiliation: Geneva Observatory, University of Geneva, Chemin des Maillettes 51, 1290 Versoix, Switzerland.
authors.forename: Pascal A
authors.initials: PA
authors.lastname: Oesch
authors.affiliation: George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Casey
authors.initials: C
authors.lastname: Papovich
authors.affiliation: Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, New South Wales 2109, Australia.|Australian Astronomical Observatory, PO Box 915, North Ryde, New South Wales 1670, Australia.
authors.forename: Lee R
authors.initials: LR
authors.lastname: Spitler
authors.affiliation: Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany.
authors.forename: Caroline M S
authors.initials: CM
authors.lastname: Straatman
authors.affiliation: George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Kim-Vy H
authors.initials: KH
authors.lastname: Tran
authors.affiliation: Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, Australian Capital Territory 2611, Australia.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Yuan