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THE DISCOVERY OF THE FIRST "CHANGING LOOK" QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI
Journal article   Open access

THE DISCOVERY OF THE FIRST "CHANGING LOOK" QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI

Stephanie M LaMassa, Sabrina Cales, Edward C Moran, Adam D Myers, Gordon T Richards, Michael Eracleous, Timothy M Heckman, Luigi Gallo and C. Megan Urry
The Astrophysical journal, v 800(2)
20 Feb 2015
DOI: https://doi.org/10.1088/0004-637X/800/2/144
url
https://doi.org/10.1088/0004-637x/800/2/144View
Published, Version of Record (VoR)Maybe Open Access (Publisher Bronze),  Open
url
https://doi.org/10.1088/0004-637X/800/2/144View
Published, Version of Record (VoR) Open

Abstract

accretion, accretion disks line: profiles quasars: emission lines quasars: general quasars: individual (SDSS J015957.64+003310.5) quasars: supermassive black holes ESI Highly Cited Paper (Incites)
ABSTRACT SDSS J015957.64+003310.5 is an X-ray selected, z = 0.31 active galactic nucleus (AGN) from the Stripe 82X survey that transitioned from a Type 1 quasar to a Type 1.9 AGN between 2000 and 2010. This is the most distant AGN, and first quasar, yet observed to have undergone such a dramatic change. We re-observed the source with the double spectrograph on the Palomar 5 m telescope in 2014 July and found that the spectrum is unchanged since 2010. From fitting the optical spectra, we find that the AGN flux dropped by a factor of 6 between 2000 and 2010 while the broad H emission faded and broadened. Serendipitous X-ray observations caught the source in both the bright and dim state, showing a similar 2-10 keV flux diminution as the optical while lacking signatures of obscuration. The optical and X-ray changes coincide with g-band magnitude variations over multiple epochs of Stripe 82 observations. We demonstrate that variable absorption, as might be expected from the simplest AGN unification paradigm, does not explain the observed photometric or spectral properties. We interpret the changing state of J0159+0033 to be caused by dimming of the AGN continuum, reducing the supply of ionizing photons available to excite gas in the immediate vicinity around the black hole. J0159+0033 provides insight into the intermittency of black hole growth in quasars, as well as an unprecedented opportunity to study quasar physics (in the bright state) and the host galaxy (in the dim state), which has been impossible to do in a single sources until now.

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Astronomy & Astrophysics
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