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Investigating Overdensities around z > 6 Galaxies through ALMA Observations of [C II]

Miller, Tim B. and Chapman, Scott C. and Hayward, Christopher C. and Behroozi, Peter S. and Bradford, Matt and Willott, Chris J. and Wagg, Jeff (2020) Investigating Overdensities around z > 6 Galaxies through ALMA Observations of [C II]. Astrophysical Journal, 889 (2). Art. No. 98. ISSN 1538-4357.

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We present a search for companion [C II] emitters to known luminous sources at 6 < z < 6.5 in deep, archival ALMA observations. The observations are deep enough to detect sources with L_([CII])∼10⁸ at z ∼6. We identify three new robust line detections from a blind search of five deep fields centered on ultraluminous infrared galaxies and QSOs. We calculate the volume density of companions and find a relative overdensity of 6⁺⁴₋₃ and 86⁺⁶⁰₋₃₇ when comparing to current observational constraints and theoretical predictions, respectively. These results suggest that the central sources may be highly biased tracers of mass in the early universe. We find these companion lines to have comparable properties to other known galaxies at the same epoch. All companions lie less than 650 km s⁻¹ and between 25 and 60 kpc (projected) from their central source. To place these discoveries in context, we employ a mock galaxy catalog to estimate the luminosity function for [C II] during reionization and compare to our observations. The simulations support this result by showing a similar level of elevated counts found around such luminous [C II] sources.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hayward, Christopher C.0000-0003-4073-3236
Willott, Chris J.0000-0002-4201-7367
Additional Information:© 2020 The American Astronomical Society. Received 2018 September 19; revised 2019 December 16; accepted 2019 December 16; published 2020 January 29. We thank the anonymous referees, whose suggestions greatly improved the manuscript. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00815.S., ADS/JAO.ALMA#2011.0.00243.S, and ADS/JAO.ALMA#2011.0.00206.S. ALMA is a partnership of the ESO (representing its member states), NSF (USA), and NINS (Japan), together with the NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by the ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. T.B.M. would like to thank the Killam Trust and the Gruber Foundation for support. S.C.C. acknowledges the Killam Trust, NSERC, and CFI for support. Support for P.B. through program No. HST-HF2-51353.001-A was provided by NASA through a Hubble Fellowship grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. The Flatiron Institute is supported by the Simons Foundation.
Funding AgencyGrant Number
Gruber FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
NASA Hubble FellowshipHST-HF2-51353.001-A
Simons FoundationUNSPECIFIED
Subject Keywords:Quasar-galaxy pairs; Reionization; Submillimeter astronomy; High-redshift galaxies; Galaxies
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Quasar-galaxy pairs (1316); Reionization (1383); Submillimeter astronomy (1647); High-redshift galaxies (734); Galaxies (573)
Record Number:CaltechAUTHORS:20200129-110820883
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Official Citation:Tim B. Miller et al 2020 ApJ 889 98
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100985
Deposited By: Tony Diaz
Deposited On:29 Jan 2020 19:31
Last Modified:29 Jan 2020 19:31

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