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The Changing-look Quasar Mrk 590 Is Awakening

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posted on 10.09.2019, 14:05 by S Mathur, KD Denney, A Gupta, M Vestergaard, G De Rosa, Y Krongold, F Nicastro, J Collinson, M Goad, K Korista, RW Pogge, BM Peterson
Mrk 590 was originally classified as a Seyfert 1 galaxy, but then it underwent dramatic changes: the nuclear luminosity dropped by over two orders of magnitude and the broad emission lines all but disappeared from the optical spectrum. Here we present follow-up observations to the original discovery and characterization of this "changing-look" active galactic nucleus (AGN). The new Chandra and Hubble Space Telescope observations from 2014 show that Mrk 590 is awakening, changing its appearance again. While the source continues to be in a low state, its soft excess has re-emerged, though not to the previous level. The UV continuum is brighter by more than a factor of two and the broad Mg ii emission line is present, indicating that the ionizing continuum is also brightening. These observations suggest that the soft excess is not due to reprocessed hard X-ray emission. Instead, it is connected to the UV continuum through warm Comptonization. Variability of the Fe Kα emission lines suggests that the reprocessing region is within ~10 lt-yr or 3 pc of the central source. The change in AGN type is neither due to obscuration nor due to one-way evolution from Type 1 to Type 2, as suggested in the literature, but may be related to episodic accretion events.


Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number G04-15114X to S.M. issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. Support for the HST program number GO-13185 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. K.D.D. was supported by an NSF AAPF fellowship awarded under NSF grant AST-1302093 while she worked on this project. M.V. gratefully acknowledges support from the Danish Council for Independent Research via grant number DFF 4002-00275.



The Astrophysical Journal, 2018, 866:123 (5pp)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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American Astronomical Society, IOP Publishing





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