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Title: The Changing-look Quasar Mrk 590 Is Awakening
Authors: Mathur, S
Denney, KD
Gupta, A
Vestergaard, M
De Rosa, G
Krongold, Y
Nicastro, F
Collinson, J
Goad, M
Korista, K
Pogge, RW
Peterson, BM
First Published: 19-Oct-2018
Publisher: American Astronomical Society, IOP Publishing
Citation: The Astrophysical Journal, 2018, 866:123 (5pp)
Abstract: 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.
DOI Link: 10.3847/1538-4357/aadd91
ISSN: 0004-637X
eISSN: 1538-4357
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2018, American Astronomical Society, IOP Publishing. Deposited with reference to the publisher’s open access archiving policy. (
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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