Long-term optical spectral monitoring of a changing-look AGN NGC 3516 I: Continuum and broad-line flux variability

Abstract

Here we present the long-term optical spectral monitoring of a changing-look active galactic nuclei (AGN) NGC 3516 that covers 22 years (from 1996 to 2018). We explore a variability in the broad lines and continuum, finding that the continuum is changing by more than a factor of 2, while the broad lines are varying by more than a factor of 10. The minimum of activity is observed in 2014, when the broad lines almost disappeared. We confirm that NGC 3516 is a changing-look AGN, and the absorption seen in the UV and X-ray may indicate that there is an obscuring region which is responsible for this. The line profiles are also changing. The mean profiles of the broad Halpha and Hbeta lines show shoulder-like structure in the wings, and enhanced peak, that may indicate a complex BLR. The rms-profiles of both lines seem to have the same shape and width of around 4200 km/s, indicating practically the same kinematics in the Halpha and Hbeta emitting regions. Measured time-lags between the continuum and Halpha and Hbeta broad-line variability are ~15 and 17 days, respectively, that in combination with the broad lines width allows us to estimate the NGC 3516 central black hole mass. We find that the black hole mass is 4.73+-1.40 x 10^7M_sun which is in agreement with previous estimates.

Accepted for publication in MNRAS

References in corpus (9)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• The black hole mass - stellar velocity dispersion relation of narrow-line Seyfert 1 galaxies
• The flux ratio of the [OIII] 5007,4959 lines in AGN: Comparison with theoretical calculations
• Long-term variability of the optical spectra of NGC 4151: I. Light curves and flux correlations
• Spectral optical monitoring of 3C390.3 in 1995-2007: I. Light curves and flux variation of the continuum and broad lines
• Spectral optical monitoring of the double peaked emission line AGN Arp 102B: II. Variability of the broad line properties
• Long-term optical spectral monitoring of NGC 7469
• Formation of Ionization-Cone Structures in Active Galactic Nuclei: I. Stationary Model and Linear Stability Analysis
• A Multiwavelength Cross-Correlation Variability Study of Fermi-LAT Blazars

Cited by in corpus (12)

• A possible mechanism for multiple changing look phenomenon in Active Galactic Nuclei
• BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
• Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 3516
• Changing-look event in NGC 3516: continuum or obscuration variability?
• A flare in the optical spotted in the changing-look Seyfert NGC 3516
• A Systematic Analysis of Stellar Populations in the Host Galaxies of Changing-look AGNs
• The post-maximum behaviour of the changing-look Seyfert galaxy NGC 1566
• Kinematic signatures of reverberation mapping of close binaries of supermassive black holes in active galactic nuclei III. The case of elliptical orbits
• Discovery of late-time X-ray flare and anomalous emission line enhancement after the nuclear optical outburst in a narrow-line Seyfert 1 Galaxy
• On possible proxies of AGN light curves cadence selection in future time domain surveys
• Detecting subparsec super-massive binary black holes: Long termmonitoring perspective
• A Systematic Survey for z < 0.04 Changing-Look AGNs