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A study of heating and cooling of the ISM in NGC 1097 with Herschel-pacs and Spitzer-IRS Gil De Paz, Armando 52 Far-infrared spectroscopy Nearby galaxies survey Star-forming galaxies Interstellar-medium C-ii Photodissociation regions Molecular-hydrogen Translucent clouds Seyfert-galaxies Iron project Astrofísica Astronomía (Física) © 2012. The American Astronomical Society. All rights reserved. Artículo firmado por 41 autores. We thank Gregory Brunner and Sebastian Haan for the code used to construct the Spitzer-IRS maps. We also thank Dario Fadda and Jeff Jacobson for software support. This work is partially based on observations made with Herschel, a European Space Agency Cornerstone Mission with significant participation by NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. PACS has been developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAF-IFSI/OAA/OAP/OAT, LENS, SISSA (Italy); and IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESA-PRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI/INAF (Italy), and CICYT/MCYT (Spain). Data presented in this paper were analyzed using The Herschel Interactive Processing Environment (HIPE), a joint development by the Herschel Science Ground Segment Consortium, consisting of ESA, the NASA Herschel Science Center, and the HIFI, PACS, and SPIRE consortia. NGC 1097 is a nearby Seyfert 1 galaxy with a bright circumnuclear starburst ring, a strong large-scale bar, and an active nucleus. We present a detailed study of the spatial variation of the far-infrared (FIR) [C II]158 μm and [O I]63 μm lines and mid-infrared H2 emission lines as tracers of gas cooling, and of the polycyclic aromatic hydrocarbon (PAH) bands as tracers of the photoelectric heating, using Herschel-PACS and Spitzer-IRS infrared spectral maps. We focus on the nucleus and the ring, and two star-forming regions (Enuc N and Enuc S). We estimated a photoelectric gas heating efficiency ([C II]158 μm+[O I]63 μm)/PAH in the ring about 50% lower than in Enuc N and S. The average 11.3/7.7 μm PAH ratio is also lower in the ring, which may suggest a larger fraction of ionized PAHs, but no clear correlation with [C II]158 μm/PAH(5.5-14 μm) is found. PAHs in the ring are responsible for a factor of two more [C II]158 μm and [O I]63 μm emission per unit mass than PAHs in the Enuc S. spectral energy distribution (SED) modeling indicates that at most 25% of the FIR power in the ring and Enuc S can come from high-intensity photodissociation regions (PDRs), in which case G_0 ~ 10^2.3 and n_H ~ 10^3.5 cm^–3 in the ring. For these values of G_0 and n_H, PDR models cannot reproduce the observed H_2 emission. Much of the H_2 emission in the starburst ring could come from warm regions in the diffuse interstellar medium that are heated by turbulent dissipation or shocks. NASA through JPL/Caltech BMVIT (Austria) ESA-PRODEX (Belgium) CEA/CNES (France) DLR (Germany) ASI/INAF (Italy) Comisión Interministerial de Ciencia y Tecnología (CICYT) Ministerio de Ciencia y Tecnología (MCYT) Depto. de Física de la Tierra y Astrofísica Fac. de Ciencias Físicas TRUE pub 2023-06-20T04:03:11Z 2023-06-20T04:03:11Z 2012-06-01 journal article https://hdl.handle.net/20.500.14352/44853 0004-637X 10.1088/0004-637X/751/2/144 eng open access application/pdf American Astronomical Society