COLDz: A High Space Density of Massive Dusty Starburst Galaxies ∼1 Billion Years after the Big Bang
- Creators
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Riechers, Dominik A.
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Hodge, Jacqueline A.
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Pavesi, Riccardo
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Daddi, Emanuele
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Decarli, Roberto
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Ivison, Rob J.
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Sharon, Chelsea E.
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Smail, Ian
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Walter, Fabian
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Aravena, Manuel
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Capak, Peter L.
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Carilli, Christopher L.
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Cox, Pierre
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da Cunha, Elisabete
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Dannerbauer, Helmut
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Dickinson, Mark
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Neri, Roberto
- Wagg, Jeff
Abstract
We report the detection of CO(J = 2 → 1) emission from three massive dusty starburst galaxies at z > 5 through molecular line scans in the NSF's Karl G. Jansky Very Large Array (VLA) CO Luminosity Density at High Redshift (COLDz) survey. Redshifts for two of the sources, HDF 850.1 (z = 5.183) and AzTEC-3 (z = 5.298), were previously known. We revise a previous redshift estimate for the third source GN10 (z = 5.303), which we have independently confirmed through detections of CO J = 1 → 0, 5 → 4, 6 → 5, and [C II] 158 μm emission with the VLA and the NOrthern Extended Milllimeter Array. We find that two currently independently confirmed CO sources in COLDz are "optically dark", and that three of them are dust-obscured galaxies at z > 5. Given our survey area of ~60 arcmin², our results appear to imply a ~6–55 times higher space density of such distant dusty systems within the first billion years after the Big Bang than previously thought. At least two of these z > 5 galaxies show star formation rate surface densities consistent with so-called "maximum" starbursts, but we find significant differences in CO excitation between them. This result may suggest that different fractions of the massive gas reservoirs are located in the dense, star-forming nuclear regions—consistent with the more extended sizes of the [C II] emission compared to the dust continuum and higher [C II]-to-far-infrared luminosity ratios in those galaxies with lower gas excitation. We thus find substantial variations in the conditions for star formation between z > 5 dusty starbursts, which typically have dust temperatures that are ~57% ± 25% warmer than starbursts at z = 2–3 due to their enhanced star formation activity.
Additional Information
© 2020 The American Astronomical Society. Received 2020 January 20; revised 2020 April 17; accepted 2020 April 21; published 2020 May 28. We thank the anonymous referee for a careful reading of the manuscript and helpful comments that led to improvements in the structure and content of this work. We also thank Christian Henkel for the original version of the LVG code, Daizhong Liu for sharing results on the de-blended photometry of GN10 in an early stage of the analysis and the source data used in Figure 11, Zhi-Yu Zhang for enlightening discussions, and Ugne Dudzeviciute for help with the AS2COSMOS number density calculations. D.R. and R.P. acknowledge support from the National Science Foundation under grant Nos. AST-1614213 and AST-1910107 to Cornell University. D.R. also acknowledges support from the Alexander von Humboldt Foundation through a Humboldt Research Fellowship for Experienced Researchers. J.H. acknowledges support of the VIDI research program with project No. 639.042.611, which is (partly) financed by the Netherlands Organization for Scientific Research (NWO). I.R.S. acknowledges support from STFC (ST/P000541/1). H.D. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under the 2014 Ramón y Cajal program RYC-2014-15686 and AYA2017-84061-P, the latter one being co-financed by FEDER (European Regional Development Funds). The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Facilities: VLA - Very Large Array, NOEMA. -Attached Files
Published - Riechers_2020_ApJ_895_81.pdf
Submitted - 2004.10204.pdf
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Additional details
- Eprint ID
- 103520
- Resolver ID
- CaltechAUTHORS:20200528-130932597
- AST-1614213
- NSF
- AST-1910107
- NSF
- Alexander von Humboldt Foundation
- 639.042.611
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- ST/P000541/1
- Science and Technology Facilities Council (STFC)
- RYC-2014-15686
- Ministerio de Economía, Industria y Competitividad (MINECO)
- AYA2017-84061-P
- Ministerio de Ciencia, Innovación y Universidades (MICIU)
- European Regional Development Funds (ERDF)
- Created
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2020-05-28Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)