TY - JOUR
T1 - Optical Variability of the Dwarf AGN NGC 4395 from the Transiting Exoplanet Survey Satellite
AU - Burke, Colin J.
AU - Shen, Yue
AU - Chen, Yu Ching
AU - Scaringi, Simone
AU - Faucher-Giguere, Claude Andre
AU - Liu, Xin
AU - Yang, Qian
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/8/20
Y1 - 2020/8/20
N2 - We present optical light curves from the Transiting Exoplanet Survey Satellite (TESS) for the archetypical dwarf active galactic nucleus (AGN) in the nearby galaxy NGC 4395 hosting a ∼105 M o˙ supermassive black hole (SMBH). Significant variability is detected on timescales from weeks to hours before reaching the background noise level. The ∼month-long, 30 minute-cadence, high-precision TESS light curve can be well fit by a simple damped random walk (DRW) model, with the damping timescale τ DRW constrained to be 2.3+1.8-0.7 days (1σ). NGC 4395 lies almost exactly on the extrapolation of the τDRW-MBH relation measured for AGNs with BH masses that are more than three orders of magnitude larger. The optical variability periodogram can be well fit by a broken power law with the high-frequency slope (-1.88 ± 0.15) and the characteristic timescale (days) consistent with the DRW model within 1σ. This work demonstrates the power of TESS light curves in identifying low-mass accreting SMBHs with optical variability, and a potential global τ-MBH relation that can be used to estimate SMBH masses with optical variability measurements.
AB - We present optical light curves from the Transiting Exoplanet Survey Satellite (TESS) for the archetypical dwarf active galactic nucleus (AGN) in the nearby galaxy NGC 4395 hosting a ∼105 M o˙ supermassive black hole (SMBH). Significant variability is detected on timescales from weeks to hours before reaching the background noise level. The ∼month-long, 30 minute-cadence, high-precision TESS light curve can be well fit by a simple damped random walk (DRW) model, with the damping timescale τ DRW constrained to be 2.3+1.8-0.7 days (1σ). NGC 4395 lies almost exactly on the extrapolation of the τDRW-MBH relation measured for AGNs with BH masses that are more than three orders of magnitude larger. The optical variability periodogram can be well fit by a broken power law with the high-frequency slope (-1.88 ± 0.15) and the characteristic timescale (days) consistent with the DRW model within 1σ. This work demonstrates the power of TESS light curves in identifying low-mass accreting SMBHs with optical variability, and a potential global τ-MBH relation that can be used to estimate SMBH masses with optical variability measurements.
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U2 - 10.3847/1538-4357/aba3ce
DO - 10.3847/1538-4357/aba3ce
M3 - Article
AN - SCOPUS:85090413345
VL - 899
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 136
ER -