z-GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies: I. Overview
Journal article, 2023
Using the IRAM NOrthern Extended Millimetre Array (NOEMA), we conducted a Large Programme (z-GAL) to measure redshifts for 126 bright galaxies detected in the Herschel Astrophysical Large Area Survey (H-ATLAS), the HerMES Large Mode Survey (HeLMS), and the Herschel Stripe 82 (HerS) Survey. We report reliable spectroscopic redshifts for a total of 124 of the Herschel-selected galaxies. The redshifts are estimated from scans of the 3 and 2-mm bands (and, for one source, the 1-mm band), covering up to 31 GHz in each band, and are based on the detection of at least two emission lines. Together with the Pilot Programme, where 11 sources had their spectroscopic redshifts measured, our survey has derived precise redshifts for 135 bright Herschel-selected galaxies, making it the largest sample of high-z galaxies with robust redshifts to date. Most emission lines detected are from 12CO (mainly from J = 2 1 to 5 4), with some sources seen in [CI] and H2O emission lines. The spectroscopic redshifts are in the range 0.8 < z < 6.55 with a median value of z = 2.56 ± 0.10, centred on the peak epoch of galaxy formation. The linewidths of the sources are large, with a mean value for the full width at half maximum I- V of 590 ± 25 km s-1 and with 35% of the sources having widths of 700 km s-1 < I- V < 1800 km s-1. Most of the sources are unresolved or barely resolved on scales of ∼2 to 3; (or linear sizes of ∼15 - 25 kpc, unlensed). Some fields reveal double or multiple sources in line emission and the underlying dust continuum and, in some cases, sources at different redshifts. Taking these sources into account, there are, in total, 165 individual sources with robust spectroscopic redshifts, including lensed galaxies, binary systems, and over-densities. This paper presents an overview of the z-GAL survey and provides the observed properties of the emission lines, the derived spectroscopic redshifts, and a catalogue of the entire sample. The catalogue includes, for each source, the combined continuum and emission lines' maps together with the spectra for each of the detected emission lines. The data presented here will serve as a foundation for the other z-GAL papers in this series reporting on the dust emission, the molecular and atomic gas properties, and a detailed analysis of the nature of the sources. Comparisons are made with other spectroscopic surveys of high-z galaxies and future prospects, including dedicated follow-up observations based on these redshift measurements, are outlined.
Radio lines: ISM
Submillimeter: galaxies
Galaxies: high-redshift
Gravitational lensing: strong
Galaxies: ISM
Author
P. Cox
Institut d 'Astrophysique de Paris
R. Neri
Institut de Radioastronomie Millimétrique (IRAM)
S. Berta
Institut de Radioastronomie Millimétrique (IRAM)
D. Ismail
Laboratoire d'Astrophysique de Marseille
F. Stanley
Institut de Radioastronomie Millimétrique (IRAM)
A. J. Young
Rutgers University
S. Jin
Cosmic Dawn Center (DAWN)
Technical University of Denmark (DTU)
Tom Bakx
Nagoya University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
National Astronomical Observatory of Japan
A. Beelen
Laboratoire d'Astrophysique de Marseille
H. Dannerbauer
University of La Laguna
Instituto de Astrofísica de Canarias
M. Krips
Institut de Radioastronomie Millimétrique (IRAM)
M. Lehnert
CRAL Le Centre de Recherche Astronomique de Lyon
A.A. Omont
Institut d 'Astrophysique de Paris
D. A. Riechers
University of Cologne
A. J. Baker
Rutgers University
University of the Western Cape
G. J. Bendo
University of Manchester
E. Borsato
University of Padua
V. Buat
Laboratoire d'Astrophysique de Marseille
K. M. Butler
Institut de Radioastronomie Millimétrique (IRAM)
N. Chartab
University of California
A. Cooray
University of California
S. Dye
University of Nottingham
S. Eales
Cardiff University
R. Gavazzi
Laboratoire d'Astrophysique de Marseille
D. Hughes
National Institute of Astrophysics, Optics and Electronics
R. J. Ivison
University of Edinburgh
Macquarie University
European Southern Observatory (ESO)
Dublin Institute for Advanced Studies
B. M. Jones
University of Cologne
L. Marchetti
University of Cape Town
Istituto di Radioastronomia
H. Messias
Atacama Large Millimeter-submillimeter Array (ALMA)
European Southern Observatory Santiago
A. Nanni
Narodowe Centrum Badan Jadrowych
Istituto nazionale di astrofisica (INAF)
M. Negrello
Cardiff University
I. Perez-Fournon
Instituto de Astrofísica de Canarias
University of La Laguna
S. Serjeant
Open University
S. Urquhart
Open University
C. Vlahakis
National Radio Astronomy Observatory
A. Weiab
Max Planck Society
P. van der Werf
Leiden University
Chentao Yang
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 678 A26Exploring the Hidden Dusty Nuclei of Galaxies (HIDDeN)
European Research Council (ERC) (789410), 2018-10-01 -- 2023-09-30.
Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202346801