Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 4151 during Outburst Stage. II. Four Season Observation Results

Abstract

We present the results of a four-year velocity-resolved reverberation mapping (RM) campaign of the changing-look active galactic nucleus (CL-AGN) NGC 4151 during its outburst phase. By measuring the time lags of the \ha, \hb, \hg, \hei, and \heii\ emission lines, we confirm a stratified broad-line region (BLR) structure that aligns with predictions from photoionization models. Intriguingly, we observed an ``anti-breathing" phenomenon, where the lags of broad emission lines decreased with increasing luminosity, contrary to the typical expectation. This anomaly may be attributed to the influence of the ultraviolet-optical lag or non-virialized motions in the BLR gas. Velocity-resolved RM and ionization mapping analyses revealed rapid and significant changes in the BLR geometry and kinematics on timescales within one year, which cannot be interpreted by any single mechanism, such as an inhomogeneous BLR, variations in radiation pressure, or changes in the illuminated ionizing field. Additionally, the \hb\ lags of NGC 4151 and other CL-AGNs agree with the radius-luminosity relationship established for AGNs with low accretion rates, implying that the CL phenomenon is more likely driven by intrinsic changes in the accretion rate rather than obscuration. These findings provide new insights into the complex internal processes of CL-AGNs and highlight the importance of long-term, multi-line RM for understanding BLR structures, geometry, and kinematics.

16 pages, 7 figures, 3 tables, Comments welcome! Published in ApJ

References in corpus (55)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• Dynamics of line-driven disk winds in Active Galactic Nuclei
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
• Modeling reverberation mapping data II: dynamical modeling of the Lick AGN Monitoring Project 2008 dataset
• Determining Inclinations of Active Galactic Nuclei Via Their Narrow-Line Region Kinematics - I. Observational Results
• The origin of the Broad Line Region in Active Galactic Nuclei
• Changing look: from Compton-thick to Compton-thin, or the re-birth of fossil AGN
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• A Reverberation-Based Mass for the Central Black Hole in NGC 4151
• 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
• The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay Maps
• The Automatic Learning for the Rapid Classification of Events (ALeRCE) Alert Broker
• The Radius-Luminosity Relationship Depends on Optical Spectra in Active Galactic Nuclei
• Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping
• The Black Hole Mass Scale of Classical and Pseudo Bulges in Active Galaxies
• Mid-infrared variability of changing-look AGN
• Mapping the Kinematics of the Narrow-Line Region in the Seyfert Galaxy NGC 4151
• The Structure of the Broad-Line Region In Active Galactic Nuclei. II. Dynamical Modeling of Data from the AGN10 Reverberation Mapping Campaign
• The effect of radiation pressure on emission line profiles and black hole mass determination in active galactic nuclei
• Alert Classification for the ALeRCE Broker System: The Light Curve Classifier
• A possible mechanism for multiple changing look phenomenon in Active Galactic Nuclei
• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. VI. Velocity-resolved Reverberation Mapping of H$\beta$ Line
• Reverberation Mapping of Optical Emission Lines in Five Active Galaxies
• Double-peaked profiles: ubiquitous signatures of disks in the Broad Emission Lines of Active Galactic Nuclei
• Monitoring AGNs with Hβ Asymmetry. I. First Results: Velocity-resolved Reverberation Mapping
• The shape of broad-line profiles in AGN
• Optical Monitoring of the Broad-Line Radio Galaxy 3C390.3
• A Bayesian Method for the Intercalibration of Spectra in Reverberation Mapping
• The Sloan Digital Sky Survey Reverberation Mapping Project: How Broad Emission Line Widths Change When Luminosity Changes
• Photoionized HBeta Emission in NGC 5548: It Breathes!
• An Intrinsic Baldwin Effect in the H-beta Broad Emission Line in the Spectrum of NGC 5548
• Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities
• BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
• Broad-line region structure and kinematics in the radio galaxy 3C 120
• Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 3516
• Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC~4151 During Outburst Stage: Evidence for Kinematics Evolution of Broad-line Region
• Velocity-resolved Reverberation Mapping of Changing-look AGN NGC 2617
• Stability of the Broad Line Region Geometry and Dynamics in Arp 151 Over Seven Years
• The Lick AGN Monitoring Project 2016: Dynamical Modeling of Velocity-Resolved H\b{eta} Lags in Luminous Seyfert Galaxies
• Supermassive Black Hole and Broad-line Region in NGC~5548: Results from Five-season Reverberation Mapping
• Multi-Wavelength Monitoring and Reverberation Mapping of a Changing Look Event in the Seyfert Galaxy NGC 3516
• Two New "Turn-off" Changing-look Active Galactic nuclei and Implication on "Partially Obscured" AGNs
• Is the slope of the intrinsic Baldwin effect constant?
• Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns. I. Evolution of structure and kinematics
• Active Galactic Nuclei with Ultra-fast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind
• Variation of Broad Emission Lines from QSOs with Optical/UV Periodicity to Test the Interpretation of Supermassive Binary Black Holes
• Measuring the Virial Factor in SDSS DR7 AGNs with Redshifted H$\beta$ and H$\alpha$ Broad Emission Lines

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