The Close AGN Reference Survey (CARS). Mrk 1018 returns to the shadows after 30 years as a Seyfert 1

DOI: 
10.1051/0004-6361/201629102
Publication date: 
01/09/2016
Main author: 
McElroy, R. E.
IAA authors: 
Perez-Torres, M.
Authors: 
McElroy, R. E.;Husemann, B.;Davis, T. A.;Bennert, V. N.;Busch, G.;Combes, F.;Eckart, A.;Perez-Torres, M.;Powell, M.;Scharwächter, J.;Tremblay, G. R.;Urrutia, T.
Journal: 
Astronomy and Astrophysics
Refereed: 
Yes
Publication type: 
Article
Volume: 
593
Pages: 
L8
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 Hα 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.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2016A&A...593L...8M/abstract
ADS Bibcode: 
2016A&A...593L...8M
Keywords: 
galaxies: Seyfert;galaxies: individual: Mrk 1018;Astrophysics - Astrophysics of Galaxies