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A molecular Einstein ring at z = 4.12: Imaging the dynamics of a quasar host galaxy through a cosmic lens

Riechers, Dominik A. and Walter, Fabian and Brewer, Brendon J. and Carilli, Christopher L. and Lewis, Geraint F. and Bertoldi, Frank and Cox, Pierre (2008) A molecular Einstein ring at z = 4.12: Imaging the dynamics of a quasar host galaxy through a cosmic lens. Astrophysical Journal, 686 (2). pp. 851-858. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:RIEapj08

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Abstract

We present high-resolution (0.3") Very Large Array imaging of the molecular gas in the host galaxy of the high-redshift quasar PSS J2322+1944 (z = 4.12). These observations confirm that the molecular gas (CO) in the host galaxy of this quasar is lensed into a full Einstein ring and reveal the internal gas dynamics in this system. The ring has a diameter of ~1.5" and thus is sampled over ~ 20 resolution elements by our observations. Through a model-based lens inversion, we recover the velocity gradient of the molecular reservoir in the quasar host galaxy of PSS J2322+1944. The Einstein ring lens configuration enables us to zoom in on the emission and to resolve scales down to ≾ 1 kpc. From the model-reconstructed source, we find that the molecular gas is distributed on a scale of 5 kpc and has a total mass of M(H_2) = 1.7 x 10^10 M⊙. A basic estimate of the dynamical mass gives M_(dyn) = 4.4 x 10^10 sin^-2 iM⊙, that is, only ~2.5 times the molecular gas mass and ~30 times the black hole mass (assuming that the dynamical structure is highly inclined). The lens configuration also allows us to tie the optical emission to the molecular gas emission, which suggests that the active galactic nucleus does reside within, but not close to the center of, the molecular reservoir. Together with the (at least partially) disturbed structure of the CO, this suggests that the system is interacting. Such interaction, possibly caused by a major "wet" merger, may be responsible for both feeding the quasar and fueling the massive starburst of 680 M⊙ yr^-1 in this system, in agreement with recently suggested scenarios of quasar activity and galaxy assembly in the early universe.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1086/591434DOIArticle
http://www.iop.org/EJ/abstract/0004-637X/686/2/851/PublisherArticle
ORCID:
AuthorORCID
Riechers, Dominik A.0000-0001-9585-1462
Walter, Fabian0000-0003-4793-7880
Carilli, Christopher L.0000-0001-6647-3861
Bertoldi, Frank0000-0002-1707-1775
Cox, Pierre0000-0003-2027-8221
Additional Information:© 2008 The American Astronomical Society. Received 2007 December 22; accepted 2008 June 27. The authors would like to thank Dennis Downes for helpful discussions and Chien Y. Peng for providing an HST image of PSS J2322+1944. D. R. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG) through Priority Program 1177 and from NASA through Hubble Fellowship grant HST-HF- 01212.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. C. C. acknowledges support from the Max-Planck-Gesellschaft and the Alexander von Humboldt-Stiftung through the Max-Planck- Forschungspreis 2005. We thank the anonymous referee for a thorough reading of the manuscript.
Funders:
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
NASA Hubble FellowshipHST-HF-01212.01-A
NASANAS5-26555
Max-Planck-GesellschaftUNSPECIFIED
Alexander von Humboldt FoundationUNSPECIFIED
Max-Planck-Forschungspreis2005
Subject Keywords:cosmology: observations; galaxies: active; galaxies: formation; galaxies: high-redshift; galaxies: starburst; radio lines: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:RIEapj08
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:RIEapj08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13389
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 May 2009 18:17
Last Modified:17 Jul 2019 17:50

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