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Characterization of a candidate dual AGN

Lena, D. and Panizo-Espinar, G. and Jonker, P. G. and Torres, M. A. P. and Heida, M. (2018) Characterization of a candidate dual AGN. Monthly Notices of the Royal Astronomical Society, 478 (1). pp. 1326-1340. ISSN 0035-8711. doi:10.1093/mnras/sty1147.

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We present Chandra and optical observations of a candidate dual active galactic nucleus (AGN) discovered serendipitously while searching for recoiling black holes via a cross-correlation between the serendipitous XMM source catalogue (2XMMi) and SDSS-DR7 galaxies with a separation no larger than 10 times the sum of their Petrosian radii. The system has a stellar mass ratio M_1/M_2 ≈ 0.7. One of the galaxies (Source 1) shows clear evidence for AGN activity in the form of hard X-ray emission and optical emission-line diagnostics typical of AGN ionization. The nucleus of the other galaxy (Source 2) has a soft X-ray spectrum, bluer colours, and optical emission-line ratios dominated by stellar photoionization with a ‘composite’ signature, which might indicate the presence of a weak AGN. When plotted on a diagram with X-ray luminosity versus [OIII] luminosity, both nuclei fall within the locus defined by local Seyfert galaxies. From the optical spectrum, we estimate the electron densities finding n_1 < 27 e− cm^(−3) and n_2 ≈ 200 e− cm^(−3). From a 2D decomposition of the surface brightness distribution, we infer that both galaxies host rotationally supported bulges (Sérsic index <1). While the active nature of Source 1 can be established with confidence, whether the nucleus of Source 2 is active remains a matter of debate. Evidence that a faint AGN might reside in its nucleus is, however, tantalizing.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Jonker, P. G.0000-0001-5679-0695
Heida, M.0000-0002-1082-7496
Additional Information:© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2018 April 30. Received 2018 April 30; in original form 2018 February 13. Published: 03 May 2018. The authors thank K. López-López for carrying out the ACAM observations and the anonymous referee for valuable comments and suggestions. DL and PGJ acknowledge support from the European Research Council (ERC) under grant 647208 (PI Jonker). DL thanks the organizers and the participants of the Lorentz Center workshop ‘The quest for multiple supermassive black holes: a multi-messenger view’ for constructive and informative discussions; DL also thanks D. Merritt for constructive comments and C. Y. Peng and M. Cappellari for timely and clear assistance with the use of GALFIT and PPXF, respectively. MAPT acknowledges support via a Ramón y Cajal Fellowship (RYC-2015-17854). This research is based on observations made with the William Herschel Telescope, operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This reasearch has also made use of data products from the Wide field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
European Research Council (ERC)647208
Ramón y Cajal FellowshipRYC-2015-17854
Subject Keywords:galaxies: active – galaxies: interactions – galaxies: nuclei
Issue or Number:1
Record Number:CaltechAUTHORS:20180808-132302455
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Official Citation:D Lena, G Panizo-Espinar, P G Jonker, M A P Torres, M Heida; Characterization of a candidate dual AGN, Monthly Notices of the Royal Astronomical Society, Volume 478, Issue 1, 21 July 2018, Pages 1326–1340,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88662
Deposited By: Tony Diaz
Deposited On:08 Aug 2018 21:25
Last Modified:16 Nov 2021 00:28

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