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

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 Hα 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 tomore » 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.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Yale Center for Astronomy and Astrophysics, Physics Department, P.O. Box 208120, New Haven, CT 06520 (United States)
  2. Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States)
  3. Department of Physics and Astronomy 3905, University of Wyoming, 1000 E. University, Laramaie, WY 82071 (United States)
  4. Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)
  5. Department of Astronomy and Astrophysics, and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
  6. Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
  7. Department of Astronomy and Physics, Saint Mary’s University, Halifax, NS B3H 3C3 (Canada)
Publication Date:
OSTI Identifier:
22522094
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 800; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTRA; ACCRETION DISKS; BLACK HOLES; COSMIC PHOTONS; COSMIC RAY FLUX; EMISSION SPECTRA; GALAXIES; GALAXY NUCLEI; HYDROGEN; KEV RANGE; QUASARS; TELESCOPES; VARIATIONS; X RADIATION