J/ApJ/934/L37 NGC 4395 FTN/MuSCAT3 photometry obs. (Montano+, 2022) ================================================================================ Optical continuum reverberation in the dwarf Seyfert nucleus of NGC 4395. Montano J.W., Guo H., Barth A.J., Vivian U., Remigio R., Gonzalez-Buitrago D.H., Hernandez Santisteban J.V. =2022ApJ...934L..37M ================================================================================ ADC_Keywords: Galaxies, Seyfert; Photometry, ugriz Keywords: Reverberation mapping ; Seyfert galaxies Abstract: In order to constrain the size of the optical continuum emission region in the dwarf Seyfert 1 galaxy NGC 4395 through reverberation mapping, we carried out high-cadence photometric monitoring in the griz filter bands on two consecutive nights in 2022 April using the four-channel MuSCAT3 camera on the Faulkes Telescope North at Haleakala Observatory. Correlated variability across the griz bands is clearly detected, and the r-, i-, and z-band light curves show lags of 7.72_-1.09_^+1.01^, 14.16_-1.25_^+1.22^, and 20.78_-2.09_^+1.99^min with respect to the g band when measured using the full-duration light curves. When lags are measured for each night separately, the Night 2 data exhibit lower cross-correlation amplitudes and shorter lags than the Night 1 light curves. Using the full-duration lags, we find that the lag-wavelength relationship is consistent with the {tau}{propto}{lambda}^4/3^ dependence found for more luminous active galactic nuclei. Combining our results with continuum lags measured for other objects, the lag between g and z band scales with optical continuum luminosity as {tau}_gz_{propto}L^0.56+/-0.05^, similar to the scaling of broad-line region size with luminosity, reinforcing recent evidence that diffuse continuum emission from the broad-line region may contribute substantially to optical continuum variability and reverberation lags. Description: We observed NGC 4395 on 2022 April 26 (Night 1) and 27 (Night 2) (UT) using the MuSCAT3 camera on the 2m Faulkes North Telescope (FTN) located at Haleakala Observatory. FTN is a part of the Las Cumbres Observatory (LCO) Global Telescope Network. MuSCAT3 is a four-channel imager that observes simultaneously in g', r', i', and z_s_ filter bands, with a 9.1'x9.1' field of view and 0.27" pixels. Objects: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 12 25 48.86 +33 32 48.7 NGC 4395 = MaNGA 1-405438 ---------------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 20 2823 NGC 4395 FTN/MuSCAT3 photometry -------------------------------------------------------------------------------- See also: J/ApJ/632/799 : NGC4395 light curves (Peterson+, 2005) J/ApJ/650/88 : NGC4395 light curves. III. (Desroches+, 2006) J/ApJ/756/73 : gri LCs of the low-luminosity AGN NGC 4395 (Edri+, 2012) J/ApJ/821/56 : Space telescope RM project. III. NGC5548 LCs (Fausnaugh+, 2016) J/ApJ/840/41 : X-ray/UV Swift monitoring of NGC 4151 (Edelson+, 2017) J/ApJ/854/107 : Light curves of 2 Seyfert 1 galaxies (Fausnaugh+, 2018) J/ApJ/870/123 : Swift optical & UV flux of four AGNs (Edelson+, 2019) J/ApJ/899/136 : TESS light curve of AGN NGC 4395 (Burke+, 2020) J/ApJ/896/1 : SEAMBHs. XI. Mrk142 X-ray to opt. light curves (Cackett+, 2020) J/ApJ/892/93 : UV-NIR monitoring campaign of NGC 4395 (Cho+, 2020) J/ApJ/903/112 : SDSS Hb & CIV reverberation mapped AGNs (Dalla Bonta+, 2020) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 1 A1 --- Filt [griz] Filter 3- 8 F6.4 d HJD [0.26/1.55] Heliocentric Julian Date; HJD-2459695 10- 14 F5.3 cW/m2/nm Flux [0.44/1.32] Flux in units of 10^-15^erg/cm^2^/s/{AA} 16- 20 F5.3 cW/m2/nm e_Flux [0.002/0.007] Uncertainty in Flux -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Feb-2025