The Changing-Look Quasar Mrk 590 is Awakening

TY - JOUR

T1 - The Changing-Look Quasar Mrk 590 is Awakening

AU - Mathur, Smita

AU - Denney, K. D.

AU - Gupta, A.

AU - Vestergaard, M.

AU - De Rosa, G.

AU - Krongold, Y.

AU - Nicastro, F.

AU - Collinson, J.

AU - Goad, M.

AU - Korista, K.

AU - Pogge, R. W.

AU - Peterson, B. M.

PY - 2018/10/20

Y1 - 2018/10/20

N2 - 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.

AB - 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.

KW - Astrophysics - Astrophysics of Galaxies

KW - Astrophysics - High Energy Astrophysical Phenomena

U2 - 10.3847/1538-4357/aadd91

DO - 10.3847/1538-4357/aadd91

M3 - Journal article

SN - 0004-637X

VL - 866

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 123

ER -