Program: GN-2017A-Q-2

We propose monitoring observations of NGC 4395 for 2 consecutive nights, in order to measure the time lag of Balmer line variations with respect to AGN continuum variations. The expected lag is the shortest among local Seyfert 1 galaxies, providing a unique test-bed for investigating the slope and validity of the size-luminosity relation and the uncertainty of the black hole mass estimators, which are universally used for high Eddington and low Eddington AGNs. We will obtain multi-epoch spectra with a ~6 min. cadence during ~16 hr campaign, and measure the Halpha lag, which is expected to be within a couple of hours based on previous studies. Combined with the photometry campaign, which will be simultaneously performed with 1-m class telescopes, this project will provide strong constraints on the size-luminosity relation and our understanding of photoionization in the broad-line region.