Faint millimeter NIKA2 dusty star-forming galaxies: finding the high-redshift population

L.-J Bing (1) , A Beelen (1) , G Lagache (1) , R Adam (2) , P Ade (3) , H Ajeddig (4) , P André (4) , E Artis (5) , H Aussel (4) , A Benoit (6) , S Berta (7) , M Béthermin (1) , O Bourrion (5) , M Calvo (8) , A Catalano (5) , M de Petris (9) , F.-X Désert (10) , S Doyle (3) , E.F.C Driessen (7) , A Gomez (11) , J Goupy (6) , F Kéruzoré (12) , C Kramer (7, 13) , B Ladjelate (13) , S Leclercq (7) , D.-Z Liu (14) , J.-F Lestrade (15) , J.F Macías-Pérez (5) , A Maury (4) , P Mauskopf (3, 16) , F Mayet (5) , A Monfardini (6) , M Muñoz-Echeverría (5) , R Neri (7) , L Perotto (7) , G Pisano (17) , N Ponthieu (10) , V Revéret (4) , A.J Rigby (3) , A Ritacco (18) , C Romero (19) , H Roussel (20) , F Ruppin (21) , K Schuster (7) , S Shu (22) , A Sievers (13) , C Tucker (3) , M.-Y Xiao (4) , R Zylka (7)

1 LAM - Laboratoire d'Astrophysique de Marseille
2 LLR - Laboratoire Leprince-Ringuet
3 School of Physics and Astronomy [Cardiff]
4 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
5 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
6 NEEL - HELFA - Hélium : du fondamental aux applications
7 IRAM - Institut de RadioAstronomie Millimétrique
8 NEEL - Cryo - Cryogénie
9 Dipartimento di Fisica [Roma]
10 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
11 CAB - Centro de Astrobiologia [Madrid]
12 ANL - Argonne National Laboratory [Lemont]
13 IRAM - Instituto de RadioAstronomía Milimétrica
14 MPE - Max-Planck-Institut für Extraterrestrische Physik
15 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres
16 SESE - ASU School of Earth and Space Exploration
17 UGA - Université Grenoble Alpes
18 Astrophysique
19 LPENS - Laboratoire de physique de l'ENS - ENS Paris
20 IAP - Institut d'Astrophysique de Paris
21 IP2I Lyon - Institut de Physique des 2 Infinis de Lyon
22 CALTECH - California Institute of Technology

We develop a new framework to constrain the source redshift. The method jointly accounts for the detection/non-detection of spectral lines and the prior information from the photometric redshift and total infrared luminosity from spectral energy distribution analysis. The method uses the estimated total infrared luminosity to predict the line fluxes at given redshifts and generates model spectra. The redshift-dependent spectral models are then compared with the observed spectra to find the redshift. Results. We apply the aforementioned joint redshift analysis method to four high-z dusty star-forming galaxy candidates selected from the NIKA2 observations of the HLSJ091828.6+514223 (HLS) field, and further observed by NOEMA with blind spectral scans. These sources only have SPIRE/Herschel photometry as ancillary data. They were selected because of very faint or no SPIRE counterparts, as to bias the sample towards the highest redshift candidates. The method finds the spectroscopic redshift of 4 in the 5 NOEMA-counterpart detected sources, with z>3. Based on these measurements, we derive the CO/[CI] lines and millimeter continuum fluxes from the NOEMA data and study their ISM and star-formation properties. We find cold dust temperatures in some of the HLS sources compared to the general population of sub-millimeter galaxies, which might be related to the bias introduced by the SPIRE-dropout selection. Our sources, but one, have short gas depletion time of a few hundred Myrs, which is typical among high-z sub-millimeter galaxies. The only exception shows a longer gas depletion time, up to a few Gyrs, comparable to that of main-sequence galaxies at the same redshift. Furthermore, we identify a possible over-density of dusty star-forming galaxies at z=5.2, traced by two sources in our sample, as well as the lensed galaxy HLSJ091828.6+514223. (abridged)

Domaines: Astrophysique [astro-ph]

L.-J Bing, A Beelen, G Lagache, R Adam, P Ade, et al.. Faint millimeter NIKA2 dusty star-forming galaxies: finding the high-redshift population. Astronomy and Astrophysics - A&A, 2024, 683, pp.A232. ⟨10.1051/0004-6361/202243887⟩. ⟨hal-04538981⟩