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Overdensity of submillimeter galaxies around the z ≃ 2.3 MAMMOTH-1 nebula

Arrigoni Battaia, F.; Chen, Chian-Chou; Fumagalli, M.; Cai, Zheng; Calistro Rivera, G.; Xu, Jiachuan; Smail, I.; Prochaska, J.X.; Yang, Yujin; De Breuck, C.

Overdensity of submillimeter galaxies around the z ≃ 2.3 MAMMOTH-1 nebula Thumbnail


F. Arrigoni Battaia

Chian-Chou Chen

Zheng Cai

G. Calistro Rivera

Jiachuan Xu

J.X. Prochaska

Yujin Yang

C. De Breuck


In the hierarchical model of structure formation, giant elliptical galaxies form through merging processes within the highest density peaks known as protoclusters. While high-redshift radio galaxies usually pinpoint the location of these environments, we have recently discovered at z ∼ 2−3 three enormous (> 200 kpc) Lyman-α nebulae (ELANe) that host multiple active galactic nuclei (AGN) and that are surrounded by overdensities of Lyman-α emitters (LAE). These regions are prime candidates for massive protoclusters in the early stages of assembly. To characterize the star-forming activity within these rare structures – both on ELAN and protocluster scales – we have initiated an observational campaign with the James Clerk Maxwell Telescope (JCMT) and the Atacama Pathfinder EXperiment (APEX) telescopes. In this paper we report on sensitive SCUBA-2/JCMT 850 and 450 μm observations of a ∼128 arcmin2 field comprising the ELAN MAMMOTH-1, together with the peak of the hosting BOSS1441 LAE overdensity at z = 2.32. These observations unveil 4.0 ± 1.3 times higher source counts at 850 μm with respect to blank fields, likely confirming the presence of an overdensity also in obscured tracers. We find a strong detection at 850 μm associated with the continuum source embedded within the ELAN MAMMOTH-1, which – together with the available data from the literature – allow us to constrain the spectral energy distribution of this source to be of an ultra-luminous infrared galaxy (ULIRG) with a far-infrared luminosity of LFIRSF = 2.4−2.1+7.4×1012 L⊙, and hosting an obscured AGN. Such a source is thus able to power a hard photoionization plus outflow scenario to explain the extended Lyman-α, He IIλ1640, and C IVλ1549 emission, and their kinematics. In addition, the two brightest detections at 850 μm (f850 >  18 mJy) sit at the density peak of the LAEs’ overdensity, likely pinpointing the core of the protocluster. Future multiwavelength and spectroscopic datasets targeting the full extent of the BOSS1441 overdensity have the potential to firmly characterize a cosmic nursery of giant elliptical galaxies, and ultimately of a massive cluster.


Arrigoni Battaia, F., Chen, C., Fumagalli, M., Cai, Z., Calistro Rivera, G., Xu, J., …De Breuck, C. (2018). Overdensity of submillimeter galaxies around the z ≃ 2.3 MAMMOTH-1 nebula. Astronomy & Astrophysics, 620, Article A202.

Journal Article Type Article
Acceptance Date Oct 22, 2018
Online Publication Date Dec 19, 2018
Publication Date Dec 19, 2018
Deposit Date Jan 4, 2019
Publicly Available Date Jan 4, 2019
Journal Astronomy and astrophysics.
Print ISSN 0004-6361
Electronic ISSN 1432-0746
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
Volume 620
Article Number A202


Published Journal Article (4.8 Mb)

Copyright Statement
Reproduced with permission from Astronomy & Astrophysics, © ESO.

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