Variability and the size-luminosity relation of the intermediate mass AGN in NGC 4395

Abstract

We present the variability study of the lowest-luminosity Seyfert 1 galaxy NGC 4395 based on the photometric monitoring campaigns in 2017 and 2018. Using 22 ground-based and space telescopes, we monitored NGC 4395 with a $\sim$5 minute cadence during a period of 10 days and obtained light curves in the UV, V, J, H, and K/Ks bands as well as the H$\alpha$ narrow-band. The RMS variability is $\sim$0.13 mag on \emph{Swift}-UVM2 and V filter light curves, decreasing down to $\sim$0.01 mag on K filter. After correcting for continuum contribution to the H$\alpha$ narrow-band, we measured the time lag of the H$\alpha$ emission line with respect to the V-band continuum as ${55}_{-31}^{+27}$ to ${122}_{-67}^{+33}$ min. in 2017 and ${49}_{-14}^{+15}$ to ${83}_{-14}^{+13}$ min. in 2018, depending on the assumption on the continuum variability amplitude in the H$\alpha$ narrow-band. We obtained no reliable measurements for the continuum-to-continuum lag between UV and V bands and among near-IR bands, due to the large flux uncertainty of UV observations and the limited time baseline. We determined the AGN monochromatic luminosity at 5100Å $\lambda L_{\lambda }=\left(5.75\pm 0.40\right)\times 10^{39}\mathrm{erg}{\mathrm{s}}^{-1}$, after subtracting the contribution of the nuclear star cluster. While the optical luminosity of NGC 4395 is two orders of magnitude lower than that of other reverberation-mapped AGNs, NGC 4395 follows the size-luminosity relation, albeit with an offset of 0.48 dex ($\ge$2.5$\sigma$) from the previous best-fit relation of Bentz et al. (2013).

arXiv commentAccepted for publication in ApJ (Feb. 23rd, 2020). 18 pages, 10 figures

References in corpus (45)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• Cosmic-Ray Rejection by Laplacian Edge Detection
• On characterising the variability properties of X-ray light curves from active galaxies
• The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• AGN Black Hole Masses and Bolometric Luminosities
• The SDSS View of the Palomar-Green Bright Quasar Survey
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• Dwarf Galaxies with Optical Signatures of Active Massive Black Holes
• A Low-Mass Central Black Hole in the Bulgeless Seyfert 1 Galaxy NGC 4395
• An Alternative Approach To Measuring Reverberation Lags in Active Galactic Nuclei
• The evolution of massive black hole seeds
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. I. A Reverberation-Based Measurement of the Black Hole Mass
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• The Sloan Digital Sky Survey Reverberation Mapping Project: H$\alpha$ and H$\beta$ Reverberation Measurements From First-year Spectroscopy and Photometry
• The Lick AGN Monitoring Project: Reverberation Mapping of Optical Hydrogen and Helium Recombination Lines
• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. IX 10 New Observations of Reverberation Mapping and Shortened H$\beta$ Lags
• Low-mass black holes as the remnants of primordial black hole formation
• An Updated Ultraviolet Calibration for the Swift/UVOT
• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. V. A New Size-Luminosity Scaling Relation for the Broad-Line Region
• Improved Dynamical Constraints on the Masses of the Central Black Holes in Nearby Low-mass Early-type Galactic Nuclei And the First Black Hole Determination for NGC 205
• X-ray constraints on the local supermassive black hole occupation fraction
• Nearby Early-Type Galactic Nuclei at High Resolution: Dynamical Black Hole and Nuclear Star Cluster Mass Measurements
• Measuring the mass of the central black hole in the bulgeless galaxy NGC 4395 from gas dynamical modeling
• Improved Dynamical Constraints on the Mass of the central Black Hole in NGC 404
• The Structure of Nuclear Star Clusters in Nearby Late-type Spiral Galaxies from Hubble Space Telescope Wide Field Camera 3 Imaging
• Calibrating CIV-based black hole mass estimators
• A 10,000-solar-mass black hole in the nucleus of a bulgeless dwarf galaxy
• The Nuclear Spectral Energy Distribution of NGC 4395, The Least Luminous Type 1 Seyfert Galaxy
• Cepheids and Long Period Variables in NGC 4395
• Broad Band Photometric Reverberation Mapping of NGC 4395
• CIV Line-Width Anomalies: The Perils of Low S/N Spectra
• ASTRONIRCAM - infrared camera-spectrograph for Sternberg institute 2.5 METER TELESCOPE
• Optical and X-ray Variability in The Least Luminous AGN, NGC4395
• Intermediate-Mass Black Hole Growth and Feedback in Dwarf Galaxies at High Redshifts
• Exploring the local black hole mass function below $10^6$ solar masses
• The Lick AGN Monitoring Project: Photometric Light Curves and Optical Variability Characteristics
• The extended radio jet of an off-nuclear low-mass AGN in NGC 5252
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. III. Optical Variability and X-ray/UV/Optical Correlations
• A close look at the dwarf AGN of NGC 4395: optical and near-IR integral field spectroscopy
• The Seoul National University AGN monitoring project. II. BLR size and black hole mass of two AGNs
• Long-term monitoring of the broad-line region properties in a selected sample of AGN
• Reverberation Mapping of PG 0934+013 with the Southern African Large Telescope

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