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Formation of a Quasar Host Galaxy through a Wet Merger 1.4 Billion Years after the Big Bang

Riechers, Dominik A. and Walter, Fabian and Carilli, Christopher L. and Bertoldi, Frank and Momjian, Emmanuel (2008) Formation of a Quasar Host Galaxy through a Wet Merger 1.4 Billion Years after the Big Bang. Astrophysical Journal, 686 (1). L9-L12. ISSN 0004-637X. doi:10.1086/592834.

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We present high-resolution Very Large Array imaging of the molecular gas in the host galaxy of the highredshift quasar BRI 1335-0417 (z = 4.41). Our CO(J = 2 → 1) observations have a linear resolution of 0.15" (1.0 kpc) and resolve the molecular gas emission both spatially and in velocity. The molecular gas in BRI 1335-0417 is extended on scales of 5 kpc, and shows a complex structure. At least three distinct components encompassing about two-thirds of the total molecular mass of 9.2 x 10^10⊙ are identified in velocity space, which are embedded in a structure that harbors about one-third of the total molecular mass in the system. The brightest CO(J = 2 → 1) line emission region has a peak brightness temperature of 61 ± 9 K within 1 kpc diameter, which is comparable to the kinetic gas temperature as predicted from the CO line excitation. This is also comparable to the gas temperatures found in the central regions of nearby ultraluminous infrared galaxies, which are however much more compact than 1 kpc. The spatial and velocity structure of the molecular reservoir in BRI 1335-0417 is inconsistent with a simple gravitationally bound disk, but resembles a merging system. Our observations are consistent with a major, gas-rich (“wet”) merger that both feeds an accreting supermassive black hole (causing the bright quasar activity), and fuels a massive starburst that builds up the stellar bulge in this galaxy. Our study of this z > 4 quasar host galaxy may thus be the most direct observational evidence that wet mergers at high redshift are related to AGN activity.

Item Type:Article
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URLURL TypeDescription
Riechers, Dominik A.0000-0001-9585-1462
Walter, Fabian0000-0003-4793-7880
Carilli, Christopher L.0000-0001-6647-3861
Bertoldi, Frank0000-0002-1707-1775
Momjian, Emmanuel0000-0003-3168-5922
Additional Information:© 2008 The American Astronomical Society. Received 2008 July 11; accepted 2008 August 27; published 2008 September 11. We thank the anonymous referee for valuable comments that helped to improve the manuscript. D. R. acknowledges support 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 NAS 5- 26555, and from the Deutsche Forschungsgemeinschaft (DFG) Priority Program 1177. C. C. acknowledges support from the Max-Planck-Gesellschaft and the Alexander von Humboldt- Stiftung through the Max-Planck-Forschungspreis 2005.
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF-01212.01
Deutsche Forschungsgemeinschaft (DFG)1177
Alexander von Humboldt FoundationUNSPECIFIED
Subject Keywords:cosmology: observations; galaxies: active; galaxies: formation; galaxies: high-redshift; galaxies: starburst; radio lines: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:REIapjl08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13414
Deposited By: Tony Diaz
Deposited On:11 May 2009 18:59
Last Modified:08 Nov 2021 22:37

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