J/ApJ/899/136 TESS light curve of AGN NGC 4395 (Burke+, 2020)
Optical Variability of the Dwarf AGN NGC 4395 from the Transiting Exoplanet
Survey Satellite.
Burke C.J., Shen Y., Chen Y.-C., Scaringi S., Faucher-Giguere C.-A., Liu X.,
Yang Q.
<Astrophys. J., 899, 136 (2020)>
=2020ApJ...899..136B 2020ApJ...899..136B
ADC_Keywords: Galaxies, Seyfert; Active gal. nuclei; Black holes;
Photometry, VRI
Keywords: Active galactic nuclei ; Seyfert galaxies ; Black hole physics ;
Surveys
Abstract:
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 ∼105M☉ 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 τDRW constrained to be 2.3-0.7+1.8days (1σ).
NGC 4395 lies almost exactly on the extrapolation of the {tau
}DRW-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
(τbr=1/(2πfbr)=1.4-0.5+1.9days) 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 τDRW-MBH relation that
can be used to estimate SMBH masses with optical variability
measurements.
Description:
NGC 4395 was observed in Transiting Exoplanets Survey Satellite (TESS)
sector 22 with camera 2, CCD 4 during the month of 2020 March, with an
angular resolution of 42" FWHM and a wide 600-1000nm bandpass.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
12 25 48.86 +33 32 48.7 NGC4395 = NGC 4395
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 1222 Extracted TESS NGC 4395 light curves
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See also:
J/ApJ/632/799 : NGC4395 light curves (Peterson+, 2005)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJS/185/156 : The Lick AGN monitoring project (Walsh+, 2009)
J/ApJ/756/73 : gri light curves of low-luminosity AGN NGC 4395 (Edri+, 2012)
J/ApJS/217/26 : Lick AGN monitoring 2011 light curves (Barth+, 2015)
J/A+A/596/A45 : Radio light curves of 8 AGN (Fuhrmann+, 2016)
J/ApJ/828/78 : Optical monitoring of the Seyfert I NGC 3516 (Noda+, 2016)
J/ApJ/871/108 : Lick AGN monitoring project 2011 V band (Pancoast+, 2019)
J/ApJ/886/150 : VRI and K-band light curves of type 1 AGNs (Minezaki+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [1899/1927] Barycentric TESS Julian date;
BJD-2457000
13- 23 F11.6 ct/s FDIA [-1/1600]?=-1 Corrected difference imaging
analysis flux (1)
25- 33 F9.6 ct/s e_FDIA [-1/3.4]?=-1 Uncertainty in FDIA (1)
35- 45 F11.6 ct/s FDIAunc [-1/1610]?=-1 Uncorrected difference imaging
analysis flux (1)
47- 55 F9.6 ct/s e_FDIAunc [-1/3.4]?=-1 Uncertainty in FDIAunc (1)
57- 67 F11.6 ct/s FSAP [-1/1646] Simple aperture photometry flux (1)
69- 77 F9.6 ct/s e_FSAP [-1/2.94]?=-1 Uncertainy in FSAP (1)
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Note (1): Flux and flux error values of -1 indicate bad epochs that should
be discarded in analysis.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 20-Oct-2021