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Jet-related Excitation of the [C II] Emission in the Active Galaxy NGC 4258 with SOFIA

Appleton, P. N. and Díaz-Santos, T. and Fadda, D. and Ogle, P. and Togi, A. and Lanz, L. and Alatalo, K. and Fischer, C. and Rich, J. and Guillard, P. (2018) Jet-related Excitation of the [C II] Emission in the Active Galaxy NGC 4258 with SOFIA. Astrophysical Journal, 869 (1). Art. No. 61. ISSN 1538-4357. doi:10.3847/1538-4357/aaed2a.

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We detect widespread [C II] 157.7 μm emission from the inner 5 kpc of the active galaxy NGC 4258 with the SOFIA integral field spectrometer FIFI-LS. The emission is found to be associated with warm H2, distributed along and beyond the end of the southern jet, in a zone known to contain shock-excited optical filaments. It is also associated with soft X-ray hotspots, which are the counterparts of the "anomalous radio arms" of NGC 4258, and a 1 kpc long filament on the minor axis of the galaxy that contains young star clusters. Palomar CWI Hα integral field spectroscopy shows that the filament exhibits non-circular motions within NGC 4258. Many of the [C II] profiles are very broad, with the greatest line width, 455 km s^(−1), observed at the position of the southern jet bow-shock. Abnormally high ratios of L([C II])/L(FIR) and L([C II])/L(PAH 7.7 μm) are found along and beyond the southern jet and in the X-ray hotspots. These are the same regions that exhibit unusually large intrinsic [C II] line widths. This suggests that the [C II] traces warm molecular gas in shocks and turbulence associated with the jet. We estimate that as much as 40% (3.8 × 10^(39) erg s^(−1)) of the total [C II] luminosity from the inner 5 kpc of NGC 4258 arises in shocks and turbulence (<1% bolometric luminosity from the active nucleus), the rest being consistent with [C II] excitation associated with star formation. We propose that the highly inclined jet is colliding with, and being deflected around, dense irregularities in a thick disk, leading to significant energy dissipation over a wide area of the galaxy.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Appleton, P. N.0000-0002-7607-8766
Díaz-Santos, T.0000-0003-0699-6083
Fadda, D.0000-0002-3698-7076
Ogle, P.0000-0002-3471-981X
Togi, A.0000-0001-5042-3421
Lanz, L.0000-0002-3249-8224
Alatalo, K.0000-0002-4261-2326
Fischer, C.0000-0002-7299-8661
Rich, J.0000-0002-5807-5078
Guillard, P.0000-0002-2421-1350
Additional Information:© 2018 The American Astronomical Society. Received 2018 September 4; revised 2018 October 15; accepted 2018 October 29; published 2018 December 12. Results in this paper are based on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50-OK-0901 to the University of Stuttgart. Financial support for this work was provided by NASA through awards SOF-04-0205 and SOF-05-0014, issued by USRA. The authors wish to thank an anonymous referee for very useful comments. Parts of the observations described in this paper were obtained at the Hale Telescope, Palomar Observatory, as part of a continuing collaboration between the California Institute of Technology, NASA/JPL, Yale University, and the National Astronomical Observatories of China. The authors wish to thank Chris Martin, the CWI team, and the staff of the Palomar observatory for permission to use, and assistance with, the semi-private PCWI instrument. The authors also thank S. Laine (Caltech/IPAC) and M. Krause (MPIFR) for permission to use the radio continuum, CO 1–0, and processed IRAC images used in this paper. This work was initiated, in part, at the Aspen Center for Physics, which is supported by NSF grant PHY-1607611. T.D.-S. acknowledges support from ALMA-CONICYT project 31130005 and FONDE-CYT regular project 1151239.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50-OK-0901
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)31130005
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1151239
Subject Keywords:galaxies: active – galaxies: jets – galaxies: ISM – infrared: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20181212-095449834
Persistent URL:
Official Citation:P. N. Appleton et al 2018 ApJ 869 61
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91705
Deposited By: Tony Diaz
Deposited On:12 Dec 2018 18:10
Last Modified:16 Nov 2021 03:43

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