2025/06/18 by G. Lagache, Lagache, G., Mengyuan Xiao +120 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae
paper · pdf · doi:10.48550/arxiv.2506.15322
openalex publication_date 2025/06/18 · openalex created_date 2025/10/19 · openalex updated_date 2026/08/03
As part of the N2CLS Survey, we have identified a remarkable overdensity of eight bright dusty star-forming galaxies at z∼5.2 in the GOODS-N field. Three of these galaxies, N2GN101, 06, and 23 (known as GN10, HDF850.1, and S3, respectively), had previously been spectroscopically confirmed as members of the exceptional large-scale structure at z∼5.1-5.3, which is notably elongated along the line of sight, spanning 30 cMpc. We present the spectroscopic confirmation of N2GN113 at z\rm spec=5.182, a massive dusty star-forming galaxy identified through targeted NOEMA observations, and N2GN161 at z\rm spec=5.201, revealed using JWST/FRESCO data. In addition to these five spectroscopically confirmed members, we identify three further candidates with photometric redshifts consistent with the overdense structure. These galaxies are massive (with a median stellar mass of 9x 1010 M\odot) and highly obscured (with a median AV of 3.3), caught in a short-lived yet extreme starburst phase at z∼5.2. Their high SFRs (with a median of 590 M\odot yr-1), efficient baryon to stellar mass conversion (ε⋆>20%), substantial gas reservoir and dust content, suggest rapid evolution and imminent quenching. Six of these galaxies reside in overdense filaments; the remaining two may trace new distinct structures which will have to be spectroscopically confirmed. These few dusty galaxies dominate the star formation within the overdensity, contributing more than the numerous Hα emitters, and surpassing the cosmic average star formation rate density for this epoch. Their properties suggest an accelerated evolution that current models and simulations have difficulty reproducing.