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An Active Galactic Nucleus Caught in the Act of Turning Off and On

Comerford, Julia M. and Barrows, R. Scott and Müller-Sánchez, Francisco and Nevin, Rebecca and Greene, Jenny E. and Pooley, David and Stern, Daniel and Harrison, Fiona A. (2017) An Active Galactic Nucleus Caught in the Act of Turning Off and On. Astrophysical Journal, 849 (2). Art. No. 102. ISSN 1538-4357.

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We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z = 0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events that could have been triggered by a past interaction with the companion galaxy that is currently located 12.5 kpc away. We originally targeted SDSS J1354+1327 because its Sloan Digital Sky Survey spectrum has narrow AGN emission lines that exhibit a velocity offset of 69 km s−1relative to systemic. To determine the nature of the galaxy and its velocity-offset emission lines, we observed SDSS J1354+1327 with Chandra/ACIS, Hubble Space Telescope/Wide Field Camera 3, Apache Point Observatory optical longslit spectroscopy, and Keck/OSIRIS integral-field spectroscopy. We find a ~10 kpc cone of photoionized gas south of the galaxy center and a ~1 kpc semi-spherical front of shocked gas, which is responsible for the velocity offset in the emission lines, north of the galaxy center. We interpret these two outflows as the result of two separate AGN accretion events: the first AGN outburst created the southern outflow, and then <10^5 years later, the second AGN outburst launched the northern shock front. SDSS J1354+1327 is the galaxy with the strongest evidence for an AGN that has turned off and then on again, and it fits into the broader context of AGN flickering that includes observations of AGN light echoes.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Comerford, Julia M.0000-0001-8627-4907
Barrows, R. Scott0000-0002-6212-7328
Müller-Sánchez, Francisco0000-0002-2713-0628
Nevin, Rebecca0000-0003-1056-8401
Pooley, David0000-0003-4897-7833
Stern, Daniel0000-0003-2686-9241
Harrison, Fiona A.0000-0003-2992-8024
Additional Information:© 2017 The American Astronomical Society. Received 2017 July 10; revised 2017 August 28; accepted 2017 September 19; published 2017 November 6. J.M.C. thanks Nadia Zakamska for useful discussions. We also thank the anonymous referee for comments that have improved the clarity of this paper. Support for this work was provided by NASA through Chandra Award Number GO4-15113X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. Support for HST program number GO 13513 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. The scientific results reported in this article are based in part on observations made by the Chandra X-ray Observatory, and this research has made use of software provided by the Chandra X-ray Center in the application packages CIAO, ChIPS, and Sherpa. The results reported here are also based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program number GO 13513. Some of the observations reported here were obtained at the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: CXO (ACIS) - , HST (WFC3) - , APO (Dual Imaging spectrograph) - , Keck:I (OSIRIS). -
Group:Astronomy Department
Funding AgencyGrant Number
NASANAS 5-26555
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:galaxies: active – galaxies: nuclei
Issue or Number:2
Record Number:CaltechAUTHORS:20171106-100858042
Persistent URL:
Official Citation:Julia M. Comerford et al 2017 ApJ 849 102
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82976
Deposited By: Tony Diaz
Deposited On:06 Nov 2017 18:36
Last Modified:09 Mar 2020 13:19

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