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Title: The Kepler Light Curves of AGN: A Detailed Analysis

Abstract

Here, we present a comprehensive analysis of 21 light curves of Type 1 active galactic nuclei (AGN) from the Kepler spacecraft. First, we describe the necessity and development of a customized pipeline for treating Kepler data of stochastically variable sources like AGN. We then present the light curves, power spectral density functions (PSDs), and flux histograms. The light curves display an astonishing variety of behaviors, many of which would not be detected in ground-based studies, including switching between distinct flux levels. Six objects exhibit PSD flattening at characteristic timescales that roughly correlate with black hole mass. These timescales are consistent with orbital timescales or free-fall accretion timescales. We check for correlations of variability and high-frequency PSD slope with accretion rate, black hole mass, redshift, and luminosity. We find that bolometric luminosity is anticorrelated with both variability and steepness of the PSD slope. We do not find evidence of the linear rms–flux relationships or lognormal flux distributions found in X-ray AGN light curves, indicating that reprocessing is not a significant contributor to optical variability at the 0.1%–10% level.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [6]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology
  2. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy
  3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  4. Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy
  5. NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States)
  6. California Inst. of Technology (CalTech), Pasadena, CA (United States). NASA Exoplanet Science Inst.
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE; National Aeronautic and Space Administration (NASA)
OSTI Identifier:
1438562
Grant/Contract Number:  
AC02-76SF00515; PF7-180168; NAS8-03060
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 857; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; accretion; accretion disks; galaxies: active; galaxies: Seyfert; quasars: general

Citation Formats

Smith, Krista Lynne, Mushotzky, Richard F., Boyd, Patricia T., Malkan, Matt, Howell, Steve B., and Gelino, Dawn M. The Kepler Light Curves of AGN: A Detailed Analysis. United States: N. p., 2018. Web. doi:10.3847/1538-4357/aab88d.
Smith, Krista Lynne, Mushotzky, Richard F., Boyd, Patricia T., Malkan, Matt, Howell, Steve B., & Gelino, Dawn M. The Kepler Light Curves of AGN: A Detailed Analysis. United States. doi:10.3847/1538-4357/aab88d.
Smith, Krista Lynne, Mushotzky, Richard F., Boyd, Patricia T., Malkan, Matt, Howell, Steve B., and Gelino, Dawn M. Wed . "The Kepler Light Curves of AGN: A Detailed Analysis". United States. doi:10.3847/1538-4357/aab88d. https://www.osti.gov/servlets/purl/1438562.
@article{osti_1438562,
title = {The Kepler Light Curves of AGN: A Detailed Analysis},
author = {Smith, Krista Lynne and Mushotzky, Richard F. and Boyd, Patricia T. and Malkan, Matt and Howell, Steve B. and Gelino, Dawn M.},
abstractNote = {Here, we present a comprehensive analysis of 21 light curves of Type 1 active galactic nuclei (AGN) from the Kepler spacecraft. First, we describe the necessity and development of a customized pipeline for treating Kepler data of stochastically variable sources like AGN. We then present the light curves, power spectral density functions (PSDs), and flux histograms. The light curves display an astonishing variety of behaviors, many of which would not be detected in ground-based studies, including switching between distinct flux levels. Six objects exhibit PSD flattening at characteristic timescales that roughly correlate with black hole mass. These timescales are consistent with orbital timescales or free-fall accretion timescales. We check for correlations of variability and high-frequency PSD slope with accretion rate, black hole mass, redshift, and luminosity. We find that bolometric luminosity is anticorrelated with both variability and steepness of the PSD slope. We do not find evidence of the linear rms–flux relationships or lognormal flux distributions found in X-ray AGN light curves, indicating that reprocessing is not a significant contributor to optical variability at the 0.1%–10% level.},
doi = {10.3847/1538-4357/aab88d},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 857,
place = {United States},
year = {2018},
month = {4}
}

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Cited by: 9 works
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Works referenced in this record:

QSO variability: probing the starburst model
journal, April 1997

  • Aretxaga, I.; Femandes, R. C.; Terlevich, R. J.
  • Monthly Notices of the Royal Astronomical Society, Vol. 286, Issue 2
  • DOI: 10.1093/mnras/286.2.271

Gravitational microlensing is not required to explain quasar variability
journal, May 1995

  • Baganoff, Frederick K.; Malkan, Matthew A.
  • The Astrophysical Journal, Vol. 444
  • DOI: 10.1086/187848

A powerful local shear instability in weakly magnetized disks. I - Linear analysis. II - Nonlinear evolution
journal, July 1991

  • Balbus, Steven A.; Hawley, John F.
  • The Astrophysical Journal, Vol. 376
  • DOI: 10.1086/170270

BROAD-LINE REVERBERATION IN THE KEPLER -FIELD SEYFERT GALAXY Zw 229-015
journal, April 2011


Quasar Optical Variability in the Palomar-Quest Survey
journal, April 2009


Second ROSAT all-sky survey (2RXS) source catalogue
journal, March 2016


KEPLER INPUT CATALOG: PHOTOMETRIC CALIBRATION AND STELLAR CLASSIFICATION
journal, September 2011


OPTICAL VARIABILITY OF AGNs IN THE PTF/iPTF SURVEY
journal, January 2017


KEPLER OBSERVATIONS OF THE SEYFERT 1 GALAXY II ZW 229.015
journal, March 2012


Quasar Variability in the Framework of Poissonian Models
journal, November 2000

  • Cid Fernandes, R.; Sodre, Jr., L.; Vieira da Silva, Jr., L.
  • The Astrophysical Journal, Vol. 544, Issue 1
  • DOI: 10.1086/317207

Robust Locally Weighted Regression and Smoothing Scatterplots
journal, December 1979


Characteristic Ultraviolet/Optical Timescales in Active Galactic Nuclei
journal, July 2001

  • Collier, Stefan; Peterson, Bradley M.
  • The Astrophysical Journal, Vol. 555, Issue 2
  • DOI: 10.1086/321517

Variability of accretion flow in the core of the Seyfert galaxy NGC 4151
journal, July 2003


RELIABLE IDENTIFICATIONS OF ACTIVE GALACTIC NUCLEI FROM THE WISE , 2MASS, AND ROSAT ALL-SKY SURVEYS
journal, May 2012


A Cutoff in the X‐Ray Fluctuation Power Density Spectrum of the Seyfert 1 Galaxy NGC 3516
journal, April 1999

  • Edelson, Rick; Nandra, Kirpal
  • The Astrophysical Journal, Vol. 514, Issue 2
  • DOI: 10.1086/306980

X‐Ray Spectral Variability and Rapid Variability of the Soft X‐Ray Spectrum Seyfert 1 Galaxies Arakelian 564 and Ton S180
journal, April 2002

  • Edelson, Rick; Turner, T. J.; Pounds, Ken
  • The Astrophysical Journal, Vol. 568, Issue 2
  • DOI: 10.1086/323779

DISCOVERY OF A ∼5 DAY CHARACTERISTIC TIMESCALE IN THE KEPLER POWER SPECTRUM OF Zw 229–15
journal, October 2014


Long-term optical variability properties of the Palomar-Green quasars
journal, July 1999


X-ray variability of 104 active galactic nuclei
journal, August 2012


The ultraviolet/optical variability of steep-spectrum radio quasars: the change in accretion rate?
journal, June 2013


The Dip Test of Unimodality
journal, March 1985


Gravitational microlensing, quasar variability and missing matter
journal, November 1993


The variability of optically selected quasars
journal, May 1994

  • Hook, I. M.; McMahon, R. G.; Boyle, B. J.
  • Monthly Notices of the Royal Astronomical Society, Vol. 268, Issue 2
  • DOI: 10.1093/mnras/268.2.305

The K2 Mission: Characterization and Early Results
journal, April 2014

  • Howell, Steve B.; Sobeck, Charlie; Haas, Michael
  • Publications of the Astronomical Society of the Pacific, Vol. 126, Issue 938
  • DOI: 10.1086/676406

The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
journal, September 2005


Are the variability properties of the Kepler AGN light curves consistent with a damped random walk?
journal, July 2015

  • Kasliwal, Vishal P.; Vogeley, Michael S.; Richards, Gordon T.
  • Monthly Notices of the Royal Astronomical Society, Vol. 451, Issue 4
  • DOI: 10.1093/mnras/stv1230

Are the Variations in Quasar Optical flux Driven by Thermal Fluctuations?
journal, May 2009

  • Kelly, Brandon C.; Bechtold, Jill; Siemiginowska, Aneta
  • The Astrophysical Journal, Vol. 698, Issue 1
  • DOI: 10.1088/0004-637X/698/1/895

Active Galactic Nucleus Black hole mass Estimates in the era of time Domain Astronomy
journal, December 2013


Flagging and correction of pattern noise in the Kepler focal plane array
conference, July 2010

  • Kolodziejczak, Jeffery J.; Caldwell, Douglas A.; Van Cleve, Jeffery E.
  • SPIE Astronomical Telescopes + Instrumentation, SPIE Proceedings
  • DOI: 10.1117/12.857637

Tidal disruption of stars by supermassive black holes: Status of observations
journal, September 2015


REVISITING STOCHASTIC VARIABILITY OF AGNs WITH STRUCTURE FUNCTIONS
journal, July 2016


Quantifying Quasar Variability as part of a General Approach to Classifying Continuously Varying Sources
journal, December 2009

  • Kozłowski, Szymon; Kochanek, Christopher S.; Udalski, A.
  • The Astrophysical Journal, Vol. 708, Issue 2
  • DOI: 10.1088/0004-637X/708/2/927

The Palomar Transient Factory: System Overview, Performance, and First Results
journal, December 2009

  • Law, Nicholas M.; Kulkarni, Shrinivas R.; Dekany, Richard G.
  • Publications of the Astronomical Society of the Pacific, Vol. 121, Issue 886
  • DOI: 10.1086/648598

Modeling the time Variability of sdss Stripe 82 Quasars as a Damped Random walk
journal, September 2010


X-Ray Fluctuations from Locally Unstable Advection-dominated Disks
journal, June 1996

  • Manmoto, Tadahiro; Takeuchi, Mitsuru; Mineshige, Shin
  • The Astrophysical Journal, Vol. 464, Issue 2
  • DOI: 10.1086/310097

Long‐Term X‐Ray Spectral Variability in Seyfert 1 Galaxies
journal, December 2003

  • Markowitz, A.; Edelson, R.; Vaughan, S.
  • The Astrophysical Journal, Vol. 598, Issue 2
  • DOI: 10.1086/379103

Active galactic nuclei as scaled-up Galactic black holes
journal, December 2006

  • McHardy, I. M.; Koerding, E.; Knigge, C.
  • Nature, Vol. 444, Issue 7120
  • DOI: 10.1038/nature05389

On rapid migration and accretion within discs around supermassive black holes: On migration and accretion within AGN
journal, September 2011


Periodic Accretion-powered Flares from Colliding EMRIs as TDE Imposters
journal, July 2017


KEPLER OBSERVATIONS OF RAPID OPTICAL VARIABILITY IN ACTIVE GALACTIC NUCLEI
journal, November 2011


Quasi-periodic oscillations in X-ray emission from the Seyfert galaxy NGC5548
journal, January 1993

  • Papadakis, I. E.; Lawrence, A.
  • Nature, Vol. 361, Issue 6409
  • DOI: 10.1038/361233a0

A detailed X-ray variability study of the Seyfert galaxy NGC 4051
journal, January 1995

  • Papadakis, I. E.; Lawrence, A.
  • Monthly Notices of the Royal Astronomical Society, Vol. 272, Issue 1
  • DOI: 10.1093/mnras/272.1.161

Optical variability, absolute luminosity, and the Hubble diagram for QSOs
journal, September 1983

  • Pica, A. J.; Smith, A. G.
  • The Astrophysical Journal, Vol. 272
  • DOI: 10.1086/161257

Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies
journal, June 2017


INVESTIGATING THE VARIABILITY OF ACTIVE GALACTIC NUCLEI USING COMBINED MULTI-QUARTER KEPLER DATA
journal, March 2014


The time Variability of Geometrically thin Black hole Accretion Disks. i. the Search for Modes in Simulated Disks
journal, February 2009


The Transiting Exoplanet Survey Satellite
conference, August 2016

  • Ricker, G. R.; Vanderspek, R.; Winn, J.
  • SPIE Astronomical Telescopes + Instrumentation, SPIE Proceedings
  • DOI: 10.1117/12.2232071

Updating quasar bolometric luminosity corrections: Updating quasar bolometric corrections
journal, February 2012

  • Runnoe, Jessie C.; Brotherton, Michael S.; Shang, Zhaohui
  • Monthly Notices of the Royal Astronomical Society, Vol. 422, Issue 1
  • DOI: 10.1111/j.1365-2966.2012.20620.x

The first XMM-Newton slew survey catalogue: XMMSL1
journal, January 2008


Accretion-induced variability links young stellar objects, white dwarfs, and black holes
journal, October 2015

  • Scaringi, Simone; Maccarone, Thomas J.; Körding, Elmar
  • Science Advances, Vol. 1, Issue 9
  • DOI: 10.1126/sciadv.1500686

Pan-STARRS1 variability of XMM-COSMOS AGN: I. Impact on photometric redshifts⋆⋆⋆
journal, December 2015


Pan-STARRS1 variability of XMM-COSMOS AGN: II. Physical correlations and power spectrum analysis
journal, January 2016


The Two Micron All Sky Survey (2MASS)
journal, February 2006

  • Skrutskie, M. F.; Cutri, R. M.; Stiening, R.
  • The Astronomical Journal, Vol. 131, Issue 2
  • DOI: 10.1086/498708

KSwAGS: A SWIFT X-RAY AND UV SURVEY OF THE KEPLER FIELD. I.
journal, September 2015

  • Smith, Krista Lynne; Boyd, Patricia T.; Mushotzky, Richard F.
  • The Astronomical Journal, Vol. 150, Issue 4
  • DOI: 10.1088/0004-6256/150/4/126

The flux-dependent amplitude of broadband noise variability in X-ray binaries and active galaxies
journal, May 2001


X-ray variability of NGC 3227 and 5506 and the nature of active galactic nucleus 'states'
journal, October 2005


Measuring the broad-band power spectra of active galactic nuclei with RXTE
journal, May 2002


On characterizing the variability properties of X-ray light curves from active galaxies
journal, November 2003


The high frequency power spectrum of Markarian 766
journal, May 2003


ESTIMATING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE Mg II λ2800 EMISSION LINE
journal, December 2009


KEPLER PHOTOMETRY OF FOUR RADIO-LOUD ACTIVE GALACTIC NUCLEI IN 2010-2012
journal, July 2013


On the variability of quasars: a link between the Eddington ratio and optical variability?: Eddington ratio and optical variability?
journal, December 2007

  • Wilhite, Brian C.; Brunner, Robert J.; Grier, Catherine J.
  • Monthly Notices of the Royal Astronomical Society, Vol. 383, Issue 3
  • DOI: 10.1111/j.1365-2966.2007.12655.x

The dependence of quasar variability on black hole mass
journal, March 2007


The Wide-Field Infrared Survey Explorer (Wise): Mission Description and Initial On-Orbit Performance
journal, November 2010


Is Quasar Optical Variability a Damped Random Walk?
journal, February 2013


The Correlations Between Optical Variability and Physical Parameters of Quasars in sdss Stripe 82
journal, October 2012


    Works referencing / citing this record:

    The remarkable X-ray variability of IRAS 13224–3809 – I. The variability process
    journal, September 2018

    • Alston, W. N.; Fabian, A. C.; Buisson, D. J. K.
    • Monthly Notices of the Royal Astronomical Society, Vol. 482, Issue 2
    • DOI: 10.1093/mnras/sty2527

    The remarkable X-ray variability of IRAS 13224–3809 – I. The variability process
    journal, September 2018

    • Alston, W. N.; Fabian, A. C.; Buisson, D. J. K.
    • Monthly Notices of the Royal Astronomical Society, Vol. 482, Issue 2
    • DOI: 10.1093/mnras/sty2527