We present wide-field mapping at 850 μm and 450 μm of the z = 2.85 protocluster in the HS1549+19 field using the Submillimetre Common User Bolometer Array 2 (SCUBA-2). Spectroscopic follow-up of 18 bright sources selected at 850 μm, using the Nothern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter Array (ALMA), confirms the majority lies near z∼ 2.85 and are likely members of the structure. Interpreting the spectroscopic redshifts as distance measurements, we find that the SMGs span 90 Mpc2 in the plane of the sky and demarcate a 4100 Mpc3 "pancake"-shaped structure in three dimensions. We find that the high star-formation rates (SFRs) of these SMGs result in a total SFR of 20,000 M⊙ yr−1 only from the brightest galaxies in the protocluster. These rapidly star-forming SMGs can be interpreted as massive galaxies growing rapidly at large cluster-centric distances before collapsing into a virialized structure. We find that the SMGs trace the Lyman-α surface density profile. Comparison with simulations suggests that HS1549+19 could be building a structure comparable to the most massive clusters in the present-day Universe.
Cite
@article{arxiv.2406.16637,
title = {A 100 Mpc$^2$ structure traced by hyperluminous galaxies around a massive $z$ = 2.85 protocluster},
author = {George C. P. Wang and Scott C. Chapman and Nikolaus Sulzenauer and Frank Bertoldi and Christopher C. Hayward and Ryley Hill and Satoshi Kikuta and Yuichi Matsuda and Douglas Rennehan and Douglas Scott and Ian Smail and Charles C. Steidel},
journal= {arXiv preprint arXiv:2406.16637},
year = {2024}
}