J/ApJ/899/136ivo://CDS.VizieR/J/ApJ/899/136doi:10.26093/cds/vizier.18990136CDSBurke C.J.Shen Y.Chen Y.-C.Scaringi S.Faucher-Giguere C.-A.Liu X.,Yang Q.2021-12-03T13:06:51Z2021-11-04T07:56:41ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frseyfert-galaxiesactive-galactic-nucleiblack-holesinfrared-photometryvisible-astronomyphotometryWe 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{sun} 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 {tau}DRW constrained to be 2.3_-0.7_^+1.8^days (1{sigma}). NGC 4395 lies almost exactly on the extrapolation of the {tau }_DRW_-M_BH_ 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 ({tau}_br_=1/(2{pi}f_br_)=1.4_-0.5_^+1.9^days) consistent with the DRW model within 1{sigma}. This work demonstrates the power of TESS light curves in identifying low-mass accreting SMBHs with optical variability, and a potential global {tau}_DRW}_-M_BH_ relation that can be used to estimate SMBH masses with optical variability measurements.2020ApJ...899..136Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/899/136CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/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)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/899/136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/899/136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/899/136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/899/136https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/899/136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/899/136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/899/136/table1Extracted TESS NGC 4395 light curvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[1899/1927] Barycentric TESS Julian date; BJD-2457000dtime.epochdoubleFDIA[-1/1600]? Corrected difference imaging analysis flux (1)ct/sphot.flux.densitydoublenullablee_FDIA[-1/3.4]? Uncertainty in FDIA (1)ct/sstat.errordoublenullableFDIAunc[-1/1610]? Uncorrected difference imaging analysis flux (1)ct/sphot.flux.densitydoublenullablee_FDIAunc[-1/3.4]? Uncertainty in FDIAunc (1)ct/sstat.errordoublenullableFSAP[-1/1646] Simple aperture photometry flux (1)ct/sphot.flux.densitydoublee_FSAP[-1/2.94]? Uncertainy in FSAP (1)ct/sstat.errordoublenullable