Understanding the origins of massive black hole seeds and their co-evolution with their host galaxy requires studying intermediate-mass black holes (IMBHs) and estimating their mass. However, measuring the mass of these IMBHs is challenging due to the high spatial resolution requirement. A spectrophotometric reverberation monitoring is performed for a low-luminosity Seyfert 1 galaxy NGC 4395 to measure the size of the broad line region (BLR) and black hole mass. The data were collected using the 1.3-m Devasthal fast optical telescope (DFOT) and 3.6-m Devasthal optical telescope (DOT) at ARIES, Nainital, over two consecutive days in March 2022. The analysis revealed strong emission lines in the spectra and light curves of merged 5100{ \AA} spectroscopic continuum flux ($f_{ \mathrm{ 5100}}$) with photometric continuum V-band and H$\alpha$, with fractional variabilities of 6.38\% and 6.31\% respectively. In comparison to several previous studies with lag estimation $<$ 90 minutes, our calculated H$\alpha$ lag supersedes by $125.0^{ +6.2}_{ -6.1}$ minutes using ICCF and { \small JAVELIN} methods. The velocity dispersion ($\sigma_{ \mathrm{ line}}$) of the broad line clouds is measured to be $544.7^{ +22.4}_{ -25.1}$ km s$^{ -1}$, yielding a black hole mass of $\sim$ $2.2^{ +0.2}_{ -0.2}\times 10^{ 4}M_{ \mathrm{ \odot}}$ and an Eddington ratio of 0.06.
Categories: astro-ph.GA