Universität zu Köln

McElroy, R. E., Husemann, B., Croom, S. M., Davis, T. A., Bennert, V. N., Busch, G., Combes, F., Eckart, A., Perez-Torres, M., Powell, M., Scharwaechter, J., Tremblay, G. R. and Urrutia, T. (2016). The Close AGN Reference Survey (CARS) Mrk 1018 returns to the shadows after 30 years as a Seyfert 1. Astron. Astrophys., 593. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

We report the discovery that the known changing look AGN Mrk 1018 has changed spectral type for a second time. New VLT-MUSE data taken in 2015 as part of the Close AGN Reference Survey (CARS) shows that the AGN has returned to its original Seyfert 1.9 classification. The CARS sample is selected to contain only bright type 1 AGN, but Mrk 1018's broad emission lines and continuum, typical of type 1 AGN, have almost entirely disappeared. We use spectral fitting of the MUSE spectrum and previously available spectra to determine the drop in broad line flux and the Balmer decrement. We find that the broad line flux has decreased by a factor of 4.75 +/- 0.5 in H alpha since an SDSS spectrum was taken in 2000. The Balmer decrement has not changed significantly implying no enhanced reddening with time, but the remaining broad lines are more asymmetric than those present in the type 1 phase. We posit that the change is due to an intrinsic drop in flux from the accretion disk rather than variable extinction or a tidal disruption event.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code McElroy, R. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Husemann, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Croom, S. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Davis, T. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bennert, V. N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Busch, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Combes, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Eckart, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Perez-Torres, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Powell, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scharwaechter, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tremblay, G. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Urrutia, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-265352
DOI:	10.1051/0004-6361/201629102
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; BROAD H-ALPHA; TIDAL DISRUPTION; EMISSION-LINES; BLACK-HOLES; GALAXIES; SPECTRA; VARIABILITY; EVOLUTION; QUASARS Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26535