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Jet-powered molecular hydrogen emission from radio galaxies

Ogle, Patrick and Boulanger, Francois and Guillard, Pierre and Evans, Daniel A. and Antonucci, Robert and Appleton, P. N. and Nesvadba, Nicole and Leipski, Christian (2010) Jet-powered molecular hydrogen emission from radio galaxies. Astrophysical Journal, 724 (2). pp. 1193-1217. ISSN 0004-637X.

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H_2 pure-rotational emission lines are detected from warm (100–1500 K) molecular gas in 17/55 (31% of) radio galaxies at redshift z < 0.22 observed with the Spitzer IR Spectrograph. The summed H_2 0–0 S(0)–S(3) line luminosities are L(H_2) = 7 × 10^(38)–2 × 10^(42) erg s^(−1), yielding warm H_2 masses up to 2 × 10^(10) M_⊙. These radio galaxies, of both FR radio morphological types, help to firmly establish the new class of radio-selected molecular hydrogen emission galaxies (radio MOHEGs). MOHEGs have extremely large H_2 to 7.7μm polycyclic aromatic hydrocarbon (PAH) emission ratios: L(H_2)/L(PAH7.7) = 0.04–4, up to a factor 300 greater than the median value for normal star-forming galaxies. In spite of large H_2 masses, MOHEGs appear to be inefficient at forming stars, perhaps because the molecular gas is kinematically unsettled and turbulent. Low-luminosity mid-IR continuum emission together with low-ionization emission line spectra indicates low-luminosity active galactic nuclei (AGNs) in all but three radio MOHEGs. The AGN X-ray emission measured with Chandra is not luminous enough to power the H_2 emission from MOHEGs. Nearly all radio MOHEGs belong to clusters or close pairs, including four cool-core clusters (Perseus, Hydra, A2052, and A2199). We suggest that the H_2 in radio MOHEGs is delivered in galaxy collisions or cooling flows, then heated by radio-jet feedback in the form of kinetic energy dissipation by shocks or cosmic rays.

Item Type:Article
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Ogle, Patrick0000-0002-3471-981X
Guillard, Pierre0000-0002-2421-1350
Appleton, P. N.0000-0002-7607-8766
Additional Information:© 2010 American Astronomical Society. Received 2009 November 10; accepted 2010 September 22; published 2010 November 11. This work is based primarily on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Supporting observations were retrieved from the Chandra archive, maintained by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory on behalf of NASA. Optical Hubble images and NUV GALEX data were retrieved via MAST, operated by the Space Telescope Science Institute for NASA. We have made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Support for this research was provided by NASA through an award issued by JPL/Caltech. We thank Bill Reach for providing us with his H_2 fitting code. We also thank Simona Giacintucci for providing the low-frequency radio flux of the MOHEG elliptical NGC 5044 in advance of publication.
Funding AgencyGrant Number
Subject Keywords:galaxies: active – galaxies: ISM – galaxies: jets – infrared: galaxies – quasars: general
Issue or Number:2
Classification Code:PACS: 98.54.Gr; 98.62.Nx; 98.62.Qz; 98.62.Py; 98.70.Qy; 98.58.Bz
Record Number:CaltechAUTHORS:20110106-111736277
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Official Citation:Patrick Ogle et al. 2010 ApJ 724 1193 doi: 10.1088/0004-637X/724/2/1193
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21626
Deposited By: Benjamin Perez
Deposited On:06 Jan 2011 20:01
Last Modified:09 Mar 2020 13:18

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