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Protoclusters as drivers of stellar mass growth in the early Universe, a case study: Taralay – a massive protocluster at z ∼ 4.57.

Authors :
Staab, Priti
Lemaux, Brian C
Forrest, Ben
Shah, Ekta
Cucciati, Olga
Lubin, Lori
Gal, Roy R
Hung, Denise
Shen, Lu
Giddings, Finn
Khusanova, Yana
Zamorani, Giovanni
Bardelli, Sandro
Cassara, Letizia Pasqua
Cassata, Paolo
Chiang, Yi-Kuan
Fudamoto, Yoshinobu
Fukushima, Shuma
Garilli, Bianca
Giavalisco, Mauro
Source :
Monthly Notices of the Royal Astronomical Society. 3/15/2024, Vol. 528 Issue 4, p6934-6958. 25p.
Publication Year :
2024

Abstract

Simulations predict that the galaxy populations inhabiting protoclusters may contribute considerably to the total amount of stellar mass growth of galaxies in the early universe. In this study, we test these predictions observationally, using the Taralay protocluster (formerly PCl J1001+0220) at z ∼ 4.57 in the COSMOS field. With the Charting Cluster Construction with VUDS and ORELSE (C3VO) survey, we spectroscopically confirmed 44 galaxies within the adopted redshift range of the protocluster (4.48 < z < 4.64) and incorporate an additional 18 galaxies from ancillary spectroscopic surveys. Using a density mapping technique, we estimate the total mass of Taralay to be ∼1.7 × 1015 M⊙, sufficient to form a massive cluster by the present day. By comparing the star formation rate density (SFRD) within the protocluster (SFRDpc) to that of the coeval field (SFRDfield), we find that SFRDpc surpasses the SFRDfield by Δlog (SFRD/M⊙yr−1 Mpc−3) = 1.08 ± 0.32 (or ∼12 ×). The observed contribution fraction of protoclusters to the cosmic SFRD adopting Taralay as a proxy for typical protoclusters is |$33.5~{{\ \rm per\ cent}}^{+8.0~{{\ \rm per\ cent}}}_{-4.3~{{\ \rm per\ cent}}}$|⁠ , a value ∼2σ higher than the predictions from simulations. Taralay contains three peaks that are 5σ above the average density at these redshifts. Their SFRD is ∼0.5 dex higher than the value derived for the overall protocluster. We show that 68 per cent of all star formation in the protocluster takes place within these peaks, and that the innermost regions of the peaks encase |$\sim 50~{{\ \rm per\ cent}}$| of the total star formation in the protocluster. This study strongly suggests that protoclusters drive stellar mass growth in the early universe and that this growth may proceed in an inside-out manner. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
528
Issue :
4
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
175912955
Full Text :
https://doi.org/10.1093/mnras/stae301