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Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel

Veilleux, S. and Meléndez, M. and Sturm, E. and Gracia-Carpio, J. and Fischer, J. and González-Alfonso, E. and Contursi, A. and Lutz, D. and Poglitsch, A. and Davies, R. and Genzel, R. and Tacconi, L. and de Jong, J. A. and Sternberg, A. and Netzer, H. and Hailey-Dunsheath, S. and Verma, A. and Rupke, D. S. N. and Maiolino, R. and Teng, S. H. and Polisensky, E. (2013) Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel. Astrophysical Journal, 776 (1). Art. No. 27. ISSN 0004-637X. doi:10.1088/0004-637X/776/1/27.

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We report the results from a systematic search for molecular (OH 119 μm) outflows with Herschel/PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7 μm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than –50 km s^(–1), is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (~145°) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km s^(–1), is seen in only four objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of ~–1000 km s^(–1) are measured in several objects, but median outflow velocities are typically ~–200 km s^(–1). While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large active galactic nucleus (AGN) fractions and luminosities [log(L_(AGN)/L_☉) ≥ 11.8 ± 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. However, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Veilleux, S.0000-0002-3158-6820
Fischer, J.0000-0001-6697-7808
Lutz, D.0000-0003-0291-9582
Genzel, R.0000-0002-2767-9653
Tacconi, L.0000-0002-1485-9401
Hailey-Dunsheath, S.0000-0002-8504-7988
Additional Information:© 2013 American Astronomical Society. Received 2013 June 17; accepted 2013 August 21; published 2013 September 23. We thank the referee for suggesting changes that helped improve this paper. Support for this work was provided by NASA through Herschel contracts 1427277 and 1454738 (S.V. and M.M.) and contracts 1364043, 1435724, and 1456609 (J.F.). S.V. also acknowledges support from the Alexander von Humboldt Foundation for a “renewed visit” to Germany following up the original 2009 award, and thanks the host institution, MPE Garching, where a portion of this paper was written. E.G.-A. is a Research Associate at the Harvard-Smithsonian Center for Astrophysics, and thanks the support by the Spanish Ministerio de Economía y Competitividad under projects AYA2010-21697-C05-0 and FIS2012-39162-C06-01. Basic research in IR astronomy at the Naval Research Laboratory is funded by the U.S. Office of Naval Research. This research made use of PySpecKit, an open-source spectroscopic toolkit hosted at This work has made use of NASA’s Astrophysics Data System Abstract Service and the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
NASA Herschel1427277
NASA Herschel1454738
NASA Herschel1364043
NASA Herschel1435724
NASA Herschel1456609
Alexander von Humboldt FoundationUNSPECIFIED
Spanish Ministerio de Economía y CompetitividadAYA2010-21697-C05-0
Spanish Ministerio de Economía y CompetitividadFIS2012-39162-C06-01
Office of Naval Research (ONR)UNSPECIFIED
Subject Keywords:galaxies: active; galaxies: evolution; ISM: jets and outflows; ISM: molecules; quasars: general
Issue or Number:1
Record Number:CaltechAUTHORS:20131104-082047378
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Official Citation:Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel S. Veilleux et al. 2013 ApJ 776 27
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42207
Deposited By: Ruth Sustaita
Deposited On:04 Nov 2013 16:45
Last Modified:10 Nov 2021 16:19

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