A Caltech Library Service

Hidden in Plain Sight: A Massive, Dusty Starburst in a Galaxy Protocluster at z = 5.7 in the COSMOS Field

Pavesi, Riccardo and Riechers, Dominik A. and Sharon, Chelsea E. and Smolčić, Vernesa and Faisst, Andreas L. and Schinnerer, Eva and Carilli, Christopher L. and Capak, Peter L. and Scoville, Nick and Stacey, Gordon J. (2018) Hidden in Plain Sight: A Massive, Dusty Starburst in a Galaxy Protocluster at z = 5.7 in the COSMOS Field. Astrophysical Journal, 861 (1). Art. No. 43. ISSN 1538-4357. doi:10.3847/1538-4357/aac6b6.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We report the serendipitous discovery of a dusty, starbursting galaxy at z = 5.667 (hereafter called CRLE) in close physical association with the "normal" main-sequence galaxy HZ10 at z = 5.654. CRLE was identified by detection of [C II], [N II], and CO(2–1) line emission, making it the highest-redshift, most luminous starburst in the COSMOS field. This massive, dusty galaxy appears to be forming stars at a rate of at least 1500 M⊙ yr^(−1) in a compact region only ~3 kpc in diameter. The dynamical and dust emission properties of CRLE suggest an ongoing merger driving the starburst, which is in a potentially intermediate stage relative to other known dusty galaxies at the same epoch. The ratio of [C II] to [N II] may suggest that an important (~15%) contribution to the [C II] emission comes from a diffuse ionized gas component, which could be more extended than the dense, starbursting gas. CRLE appears to be located in a significant galaxy overdensity at the same redshift, potentially associated with a large-scale cosmic structure recently identified in a Lyman α-emitter survey. This overdensity suggests that CRLE and HZ10 reside in a protocluster environment, offering the tantalizing opportunity to study the effect of a massive starburst on protocluster star formation. Our findings support the interpretation that a significant fraction of the earliest galaxy formation may occur from the inside out, within the central regions of the most massive halos, while rapidly evolving into the massive galaxy clusters observed in the local universe.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Pavesi, Riccardo0000-0002-2263-646X
Riechers, Dominik A.0000-0001-9585-1462
Sharon, Chelsea E.0000-0002-6250-5608
Smolčić, Vernesa0000-0002-3893-8614
Faisst, Andreas L.0000-0002-9382-9832
Schinnerer, Eva0000-0002-3933-7677
Carilli, Christopher L.0000-0001-6647-3861
Capak, Peter L.0000-0003-3578-6843
Scoville, Nick0000-0002-0438-3323
Additional Information:© 2018 The American Astronomical Society. Received 2018 March 21; revised 2018 May 15; accepted 2018 May 19; published 2018 June 29. We thank the anonymous referee for a helpful and constructive report. R.P. and D.R. acknowledge support from the National Science Foundation under grant number AST-1614213 to Cornell University. R.P. acknowledges support through award SOSPA3-008 from the NRAO. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.00928.S, 2015.1.00388.S, 2012.1.00523.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ.
Group:COSMOS, Infrared Processing and Analysis Center (IPAC), Astronomy Department
Funding AgencyGrant Number
National Radio Astronomy ObservatorySOSPA3-008
Subject Keywords:cosmology: observations – galaxies: formation – galaxies: high-redshift – galaxies: ISM – galaxies: starburst – radio lines: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20180629-110133993
Persistent URL:
Official Citation:Riccardo Pavesi et al 2018 ApJ 861 43
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87472
Deposited By: Tony Diaz
Deposited On:29 Jun 2018 18:18
Last Modified:15 Nov 2021 20:48

Repository Staff Only: item control page