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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:
Journal Article: 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.
@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 = {Wed Apr 25 00:00:00 EDT 2018},
month = {Wed Apr 25 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on April 25, 2019
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