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Title: Optical Continuum Reverberation in the Dwarf Seyfert Nucleus of NGC 4395

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 thegrizfilter bands on two consecutive nights in 2022 April using the four-channel MuSCAT3 camera on the Faulkes Telescope North at Haleakalā Observatory. Correlated variability across thegrizbands is clearly detected, and ther-,i-, andz-band light curves show lags of7.721.09+1.01,14.161.25+1.22, and20.782.09+1.99minutes with respect to thegband 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 theτλ4/3dependence found for more luminous active galactic nuclei. Combining our results with continuum lags measured for other objects, the lag betweengandzband scales with optical continuum luminosity asτgzL0.56±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.

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DOI PREFIX: 10.3847
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Journal Name:
The Astrophysical Journal Letters
Medium: X Size: Article No. L37
["Article No. L37"]
Sponsoring Org:
National Science Foundation
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