Universität zu Köln

Husemann, B., Urrutia, T., Tremblay, G. R., Krumpe, M., Dexter, J., Busch, G., Combes, F., Croom, S. M., Davis, T. A., Eckart, A., McElroy, R. E., Perez-Torres, M., Powell, M. and Scharwachter, J. (2016). The Close AGN Reference Survey (CARS) What is causing Mrk 1018's return to the shadows after 30 years? Astron. Astrophys., 593. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

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 similar to 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 similar to 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 Ly alpha blue-shifted by similar to 700 km s(-1) with respect to the systemic velocity of the galaxy. This new Ly alpha 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:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Husemann, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Urrutia, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tremblay, G. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Krumpe, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dexter, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Busch, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Combes, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Croom, S. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Davis, T. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Eckart, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED McElroy, R. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Perez-Torres, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Powell, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scharwachter, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-265347
DOI:	10.1051/0004-6361/201629245
Journal or Publication Title:	Astron. Astrophys.
Volume:	593
Date:	2016
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ACTIVE GALACTIC NUCLEI; ACCRETION DISK; BLACK-HOLES; QUASAR; VARIABILITY; LINE; OUTBURST; EVENTS; DRIVEN; UV Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26534