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The Close AGN Reference Survey (CARS) - What is causing Mrk 1018’s return to the shadows after 30 years?

Husemann, B. and Urrutia, T. and Tremblay, G. R. and Krumpe, M. and Dexter, J. and Busch, G. and Combes, F. and Croom, S. M. and Davis, T. A. and Eckart, A. and McElroy, R. E. and Pérez-Torres, M. and Powell, M. and Scharwächter, J. (2016) The Close AGN Reference Survey (CARS) - What is causing Mrk 1018’s return to the shadows after 30 years? Astronomy & Astrophysics, 593 . Art No. L9. ISSN 0004-6361. doi:10.1051/0004-6361/201629245.

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We recently discovered that the active galactic nucleus (AGN) of Mrk 1018 has changed optical type again after 30 yr as a type 1 AGN. Here we combine Chandra, NuStar, Swift, Hubble Space Telescope and ground-based observations to explore the cause of this change. The 2–10 keV flux declines by a factor of ~8 between 2010 and 2016. We show with our X-ray observation that this is not caused by varying neutral hydrogen absorption along the line-of-sight up to the Compton-thick level. The optical-UV spectral energy distributions are well fit with a standard geometrically thin optically thick accretion disc model that seems to obey the expected L ~ T^4 relation. It confirms that a decline in accretion disc luminosity is the primary origin for the type change. We detect a new narrow-line absorber in Lyα blue-shifted by ~700 km s^(-1) with respect to the systemic velocity of the galaxy. This new Lyα absorber could be evidence for the onset of an outflow or a companion black hole with associated gas that could be related to the accretion rate change. However, the low column density of the absorber means that it is not the direct cause for Mrk 1018’s changing-look nature.

Item Type:Article
Related URLs:
URLURL TypeDescription
Husemann, B.0000-0003-2901-6842
Urrutia, T.0000-0001-6746-9936
Dexter, J.0000-0003-3903-0373
Combes, F.0000-0003-2658-7893
Croom, S. M.0000-0003-2880-9197
Additional Information:© 2016 ESO. Received: 4 July 2016; Accepted: 16 August 2016; Published online 20 September 2016. Based on Cycle 17 DDT program (ID: 18789, PI: G. Tremblay) approved by the Chandra Director, Dr. Belinda Wilkes. Based on Cycle 23 DDT project with the NASA/ESA Hubble Space Telescope (ID: 14486, PI: B. Husemann) approved by HST Director Dr. Kenneth Sembach. We thank the anonymous referee for very constructive comments and suggestions that significantly helped to improve this Letter. GRT acknowledges support from the NASA through the Einstein Postdoctoral Fellowship Award Number PF-150128, 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. MK acknowledges support by DFG grant KR 3338/3-1. MAPT acknowledges support from the Spanish MINECO through grants AYA2012-38491-C02-02 and AYA2015-63939- C2-1-P. TAD acknowledges support from a Science and Technology Facilities Council Ernest Rutherford Fellowship. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020.
Subject Keywords:accretion, accretion disks – galaxies: nuclei – galaxies: Seyfert – galaxies: individual: Mrk 1018
Record Number:CaltechAUTHORS:20160916-110635722
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Official Citation:The Close AGN Reference Survey (CARS) - What is causing Mrk 1018’s return to the shadows after 30 years? B. Husemann, T. Urrutia, G. R. Tremblay, M. Krumpe, J. Dexter, G. Busch, F. Combes, S. M. Croom, T. A. Davis, A. Eckart, R. E. McElroy, M. Perez-Torres, M. Powell and J. Scharwächter A&A, 593 (2016) L9 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70399
Deposited By: Joy Painter
Deposited On:16 Sep 2016 21:15
Last Modified:11 Nov 2021 04:28

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