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

2014/12/31 by Stephanie M. LaMassa, Sabrina Cales, Edward C. Moran +7 · 11 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cosmology #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Phenomenology (philosophy) #Photon #Quasar #Spectrograph #Telescope #astro-ph.GA

paper · pdf · doi:10.1088/0004-637x/800/2/144

accepted for publication in ApJ

arxiv created 2015/01/20 · openalex publication_date 2015/02/20 · arxiv updated 2015/06/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06

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 α 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.

Citations

• The FIRST‐2MASS Red Quasar Survey
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• The Time-domain Spectroscopic Survey: Target Selection for Repeat Spectroscopy
• Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
• A parsec-scale faint jet in the nearby changing-look Seyfert galaxy Mrk 590
• The [O iii] Profiles of Infrared-selected Active Galactic Nuclei: More Powerful Outflows in the Obscured Population
• The detection and X-ray view of the changing look AGN HE 1136-2304
• Understanding extreme quasar optical variability with CRTS – I. Major AGN flares
• The Zwicky Transient Facility: Science Objectives
• The Automatic Learning for the Rapid Classification of Events (ALeRCE) Alert Broker