Velocity-Resolved Ionization Mapping of Broad Line Region. I. Insights into Diverse Geometry and Kinematics

Abstract

Broad emission lines of active galactic nuclei (AGNs) originate from the broad-line region (BLR), consisting of dense gas clouds in orbit around an accreting supermassive black hole. Understanding the geometry and kinematics of the region is crucial for gaining insights into the physics and evolution of AGNs. Conventional velocity-resolved reverberation mapping may face challenges in disentangling the degeneracy between intricate motion and geometry of this region. To address this challenge, new key constraints are required. Here, we report the discovery of an asymmetric BLR using a novel technique: velocity-resolved ionization mapping, which can map the distance of emitting gas clouds by measuring Hydrogen line ratios at different velocities. By analyzing spectroscopic monitoring data, we find that the Balmer decrement is anticorrelated with the continuum and correlated with the lags across broad emission line velocities. Some line ratio profiles deviate from the expectations for a symmetrically virialized BLR, suggesting that the red-shifted and blue-shifted gas clouds may not be equidistant from the supermassive black hole (SMBH). This asymmetric geometry might represent a formation imprint, provide new perspectives on the evolution of AGNs, and influence SMBH mass measurements.

20 pages, 10 figures, Accepted by ApJ

References in corpus (20)

• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-Line Light Curves
• Broad-line Balmer Decrements in Blue Active Galactic Nuclei
• Dust inflated accretion disc as the origin of the Broad Line Region in Active Galactic Nuclei
• Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548
• The effect of nuclear gas distribution on the mass determination of supermassive black holes
• Failed radiatively Accelerated Dusty Outflow model of the Broad Line Region in Active Galactic Nuclei. I. Analytical solution
• A Bayesian Method for the Intercalibration of Spectra in Reverberation Mapping
• Monitoring AGNs with H$\beta$ Asymmetry. III. Long-term Reverberation Mapping Results of 15 Palomar-Green Quasars
• Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC~4151 During Outburst Stage: Evidence for Kinematics Evolution of Broad-line Region
• Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 3516
• The Lick AGN Monitoring Project 2016: Dynamical Modeling of Velocity-Resolved H\b{eta} Lags in Luminous Seyfert Galaxies
• Probing the Origin of Changing-look Quasar Transitions with Chandra
• Supermassive Black Hole and Broad-line Region in NGC~5548: Results from Five-season Reverberation Mapping
• 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
• Improving the Flux Calibration in Reverberation Mapping by Spectral Fitting: Application to the Seyfert Galaxy MCG--6-30-15
• Spiral Arms in Broad-line Regions of Active Galactic Nuclei. II. Loosely Wound Cases: Reverberation Properties
• The variability of the broad-line Balmer decrement for quasars from the Sloan Digital Sky Survey Reverberation Mapping

Cited by in corpus (1)

• Broad line regions behind haze: Intrinsic shape of Br$\gamma$ line and its origin in a type-1 Seyfert galaxy