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Gas-rich mergers and feedback are ubiquitous amongst starbursting radio galaxies, as revealed by the VLA, IRAM PdBI and Herschel

Ivison, R. J. and Smail, Ian and Amblard, A. and Arumugam, V. and de Breuck, C. and Emonts, B. H. C. and Feain, I. and Greve, T. R. and Haas, M. and Ibar, E. and Jarvis, M. J. and Kovács, A. and Lehnert, M. and Nesvadba, N. P. H. and Röttgering, H. J. A. and Seymour, N. and Wylezalek, D. (2012) Gas-rich mergers and feedback are ubiquitous amongst starbursting radio galaxies, as revealed by the VLA, IRAM PdBI and Herschel. Monthly Notices of the Royal Astronomical Society, 425 (2). pp. 1320-1331. ISSN 0035-8711. doi:10.1111/j.1365-2966.2012.21544.x.

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We report new, sensitive observations of two z ∼ 3–3.5 far-infrared-luminous radio galaxies, 6C 1909+72 and B3 J2330+3927, in the ^(12)CO J = 1−0 transition with the Karl Jansky Very Large Array and at 100–500 m using Herschel, alongside new and archival ^(12)CO J = 4−3 observations from the Plateau de Bure Interferometer. We introduce a new colour–colour diagnostic plot to constrain the redshifts of several distant, dusty galaxies in our target fields. A bright SMG near 6C 1909+72 likely shares the same node or filament as the signpost active galactic nuclei (AGN), but it is not detected in ^(12)CO despite ∼20 000 km s^(−1) of velocity coverage. Also in the 6C 1909+72 field, a large, red dust feature spanning ≈500 kpc is aligned with the radio jet. We suggest several processes by which metal-rich material may have been transported, favouring a collimated outflow reminiscent of the jet-oriented metal enrichment seen in local cluster environments. Our interferometric imaging reveals a gas-rich companion to B3 J2330+3927; indeed, all bar one of the eight z ≳ 2 radio galaxies (or companions) detected in ^(12)CO provide some evidence that starburst activity in radio-loud AGN at high redshift is driven by the interaction of two or more gas-rich systems in which a significant mass of stars has already formed, rather than via steady accretion of cold gas from the cosmic web. We find that the ^(12)CO brightness temperature ratios in radio-loud AGN host galaxies are significantly higher than those seen in similarly intense starbursts where AGN activity is less pronounced. Our most extreme example, where L'_(CO4−3)/L'_(CO1−0) > 2.7, provides evidence that significant energy is being deposited rapidly into the molecular gas via X-rays and/or mechanical (‘quasar-mode’) feedback from the AGN, leading to a high degree of turbulence globally and a low optical depth in ^(12)CO – feedback that may lead to the cessation of star formation on a time-scale commensurate with that of the jet activity, ≲10 Myr.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ivison, R. J.0000-0001-5118-1313
Smail, Ian0000-0003-3037-257X
de Breuck, C.0000-0002-6637-3315
Jarvis, M. J.0000-0001-7039-9078
Lehnert, M.0000-0003-1939-5885
Seymour, N.0000-0003-3506-5536
Wylezalek, D.0000-0003-2212-6045
Additional Information:© 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS. Accepted 2012 June 17. Received 2012 June 15; in original form 2012 May 10. Article first published online: 7 Aug 2012. We are grateful to Arjun Dey, Axel Weiss and Padelis Papadopoulos for sharing their wisdom regarding superthermal Tb ratios and unpublished optical spectroscopy.We appreciate the remarkable efforts of the NRAO staff that have significantly upgraded what many of us already regarded as the finest telescope ever built. In particular, we thank Frazer Owen and Gustaaf Van Moorsel for their invaluable help with the data used here. IRS acknowledges support from STFC and through a Leverhulme Senior Fellowship. NS is the recipient of an Australian Research Council Future Fellowship. TRG acknowledges support from STFC, as well as IDA and DARK. This work is based on observations carried out with the Karl Janksy Very Large Array. The NRAO is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. It is also based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
Leverhulme TrustUNSPECIFIED
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Instituto Geográfico Nacional (IGN)UNSPECIFIED
Australian Research CouncilUNSPECIFIED
Subject Keywords:galaxies: active; galaxies: high-redshift; galaxies: starburst; infrared: galaxies; radio lines: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20121009-114135709
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Official Citation:Ivison, R. J., Smail, I., Amblard, A., Arumugam, V., De Breuck, C., Emonts, B. H. C., Feain, I., Greve, T. R., Haas, M., Ibar, E., Jarvis, M. J., Kovács, A., Lehnert, M. D., Nesvadba, N. P. H., Röttgering, H. J. A., Seymour, N. and Wylezalek, D. (2012), Gas-rich mergers and feedback are ubiquitous amongst starbursting radio galaxies, as revealed by the VLA, IRAM PdBI and Herschel. Monthly Notices of the Royal Astronomical Society, 425: 1320–1331. doi: 10.1111/j.1365-2966.2012.21544.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34788
Deposited By: Ruth Sustaita
Deposited On:09 Oct 2012 20:29
Last Modified:09 Nov 2021 23:10

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