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[C II] and CO Emission along the Bar and Counter-arms of NGC 7479

Fadda, Dario and Laine, Seppo and Appleton, Philip N. (2021) [C II] and CO Emission along the Bar and Counter-arms of NGC 7479. Astrophysical Journal, 909 (2). Art. No. 204. ISSN 0004-637X. doi:10.3847/1538-4357/abe0b8.

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We present new SOFIA [C II] and ALMA CO_(J=1→0) observations of the nearby asymmetric barred spiral galaxy NGC 7479. The data, which cover the whole bar of the galaxy and the counter-arms visible in the radio continuum, are analyzed in conjunction with a wealth of existing visible, infrared, radio, and X-ray data. As in most normal galaxies, the [C II] emission is generally consistent with emission from cooling gas excited by photoelectric heating in photodissociation regions. However, anomalously high [C II]/CO ratios are seen at the two ends of the counter-arms. Both ends show shell-like structures, possibly bubbles, in Hα emission. In addition, the southern end has [C II]-to-infrared emission ratios inconsistent with normal star formation. Because there is little H I emission at this location, the [C II] emission probably originates in warm shocked molecular gas heated by the interaction of the radio jet forming the counter-arms with the interstellar medium in the galaxy. At two other locations, the high [C II]/CO ratios provide evidence for the existence of patches of CO-dark molecular gas. The [C II] and CO observations also reveal resolved velocity components along the bar. In particular, the CO emission can be separated into two components associated with gas along the leading edge of the bar and gas trailing the bar. The trailing gas component that amounts to approximately 40% of the gas around the bar region may be related to a minor merger.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fadda, Dario0000-0002-3698-7076
Laine, Seppo0000-0003-1250-8314
Appleton, Philip N.0000-0002-7607-8766
Additional Information:© 2021 The American Astronomical Society. Received 2020 December 7; revised 2021 January 20; accepted 2021 January 26; published 2021 March 18. Based on SOFIA observations with FIFI-LS. We thank Lauranne Lanz and Isaac Shlosman for illuminating discussions and suggestions. This research is based on data and software from the following projects. The NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA) is jointly operated by USRA, under NASA contract NNA17BF53C, and DSI, under DLR contract 50 OK 0901 to the University of Stuttgart. The ALMA observatory, operated by ESO, AUI/NRAO, and NAOJ, is a partnership of ESO, NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Rep. of Korea), in cooperation with the Republic of Chile. Herschel is an ESA space observatory with instruments provided by European-led P.I. consortia and important NASA participation. The Spitzer Space Telescope is operated by JPL, Caltech, under a contract with NASA. The SDSS survey is funded by the A.P. Sloan Foundation, the Participating Institutions, NSF, the U.S. Department of Energy, NASA, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and IPAC/Caltech, is funded by NASA and NSF. The GALEX archive is hosted by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC. The Chandra Data Archive and the CIAO software are provided by the Chandra X-ray Center. Financial support for the project was provided by NASA through award SOF-06-0124 issued by USRA. Facilities: SOFIA (FIFI-LS) - , Spitzer (IRAC - , MIPS) - , Herschel (PACS - , SPIRE) - , ALMA - , GALEX - , Chandra - , SDSS - , 2MASS. - Software: astropy (Astropy Collaboration et al. 2013), sospex (Fadda & Chambers 2018,, mopex (Makovoz & Marleau 2005,, stinytim (John Krist,, CIAO (Fruscione et al. 2006,, magphys (da Cunha et al. 2008,
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50 OK 0901
Alfred P. Sloan FoundationUNSPECIFIED
Participating InstitutionsUNSPECIFIED
Max Planck SocietyUNSPECIFIED
Higher Education Funding Council for EnglandUNSPECIFIED
Subject Keywords:Barred spiral galaxies; Infrared galaxies; Molecular gas
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Barred spiral galaxies (136); Infrared galaxies (790); Molecular gas (1073)
Record Number:CaltechAUTHORS:20210325-121459311
Persistent URL:
Official Citation:Dario Fadda et al 2021 ApJ 909 204
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108557
Deposited By: Tony Diaz
Deposited On:25 Mar 2021 22:54
Last Modified:16 Nov 2021 19:12

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