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Obscured star formation in clusters at z = 1.6–2.0: massive galaxy formation and the reversal of the star formation–density relation

Smail, Ian

Obscured star formation in clusters at z = 1.6–2.0: massive galaxy formation and the reversal of the star formation–density relation Thumbnail


Authors

Profile image of Ian Smail

Ian Smail ian.smail@durham.ac.uk
Emeritus Professor



Abstract

Clusters of galaxies at z 
 1 are expected to be increasingly active sites of star formation. To test this, an 850 m survey was undertaken of eight clusters at z = 1.6–2.0 using SCUBA-2 on the James Clerk Maxwell Telescope. Mid-infrared properties were used to identify 53 probable counterparts to 45 SCUBA-2 sources with colours that suggested they were cluster members. This uncovered a modest overdensity of 850 m sources, with far-infrared luminosities of LIR ≥ 1012 L⊙ (SFR 100 M⊙ yr−1) and colours consistent with being cluster members, of a factor of 4 ± 1 within the central 1 Mpc radius of the clusters. The submillimetre photometry of these galaxies was used to estimate the total cluster star formation rates. These showed that the mass-normalized rates in the clusters are two orders of magnitude higher than in local systems, evolving as (1 + z)5.5 ± 0.6. This rapid evolution means that the mass-normalized star formation rates in these clusters matched that of average haloes in the field at z ∼ 1.8 ± 0.2 marking the epoch where the local star formation–density relation reverses in massive haloes. The estimated stellar masses of the cluster submillimetre galaxies suggests that their descendants will be amongst the most massive galaxies in z ∼ 0 clusters. This reinforces the suggestion that the majority of the massive early-type galaxy population in z ∼ 0 clusters were likely to have formed at z 1.5–2 through very active, but dust-obscured, starburst events.

Citation

Smail, I. (2024). Obscured star formation in clusters at z = 1.6–2.0: massive galaxy formation and the reversal of the star formation–density relation. Monthly Notices of the Royal Astronomical Society, 529(3), 2290-2308. https://doi.org/10.1093/mnras/stae692

Journal Article Type Article
Acceptance Date Mar 5, 2024
Online Publication Date Mar 6, 2024
Publication Date Mar 19, 2024
Deposit Date Apr 5, 2024
Publicly Available Date Apr 5, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 529
Issue 3
Pages 2290-2308
DOI https://doi.org/10.1093/mnras/stae692
Keywords Space and Planetary Science; Astronomy and Astrophysics
Public URL https://durham-repository.worktribe.com/output/2378278