The UV/optical Continuum Reverberation Mapping of Eight Active Galactic Nuclei with Swift: Further Evidence for the Outer Component

Abstract

In our previous work, we applied the ICCF-Cut method to the continuum reverberation mapping (CRM) of six active galactic nuclei (AGNs) based on the published Swift data. Extending this work, we perform a systematic AGN CRM study utilizing the Swift archive. We enlarge our sample with eight additional AGNs at $z<0.05$ with high-cadence ($<3$ days) and multiband photometric observations. Time series analysis of these light curves shows two main results: (1) The interband lags are broadly consistent with $\tau \propto {\lambda }^{4/3}$, while the average interband lags are larger than those predicted by the standard thin accretion disk model. (2) For most targets, there exists a $U$ band lag excess, which is probably due to the diffuse continuum emission from the broad-line region (BLR). We employ the ICCF-Cut method to extract the possible diffuse continuum component from the $U$ band light curves and calculate the diffuse continuum lags (${\tau }_{\mathrm{cut}}$), which are generally consistent with the lags (${\tau }_{\mathrm{jav}}$) derived by the JAVELIN Photometric Reverberation Mapping Model. Further analysis with our sample indicates a positive correlation between the diffuse continuum region size and the BLR size ($R_{\mathrm{DCR}}-R_{\mathrm{BLR}}$ relation), as well as another correlation with the luminosity ($R_{\mathrm{DCR}}-L$ relation). These findings provide further evidence for a significant contribution of diffuse continuum emission from the BLR to the AGN continuum lags.

arXiv commentAccepted for publication in ApJ, 26 pages, 16 figures, 4 tables. The processed light curves are available on Zenodo at DOI: 10.5281/zenodo.14930797

References in corpus (76)

• emcee: The MCMC Hammer
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Observational Evidence of AGN Feedback
• The Swift Ultra-Violet/Optical Telescope
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Composite Quasar Spectra From the Sloan Digital Sky Survey
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• On characterising the variability properties of X-ray light curves from active galaxies
• Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM-Newton: spectral energy distributions for the reverberation mapped sample
• The AGN Black Hole Mass Database
• An Alternative Approach To Measuring Reverberation Lags in Active Galactic Nuclei
• Is Quasar Optical Variability a Damped Random Walk?
• Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broad-Band Time Delays in NGC 5548
• Space Telescope and Optical Reverberation Mapping Project. II. Swift and HST Reverberation Mapping of the Accretion Disk of NGC 5548
• Testing thermal reprocessing in AGN accretion discs
• Generating artificial light curves: Revisited and updated
• Kepler Observations of Rapid Optical Variability in Active Galactic Nuclei
• The Sloan Digital Sky Survey Reverberation Mapping Project: H$\alpha$ and H$\beta$ Reverberation Measurements From First-year Spectroscopy and Photometry
• Reverberation mapping of Active Galactic Nuclei: from X-ray corona to dusty torus
• Quasar Accretion Disks Are Strongly Inhomogeneous
• The First Swift Intensive AGN Accretion Disk Reverberation Mapping Survey
• Are the Narrow Line Regions in Active Galaxies Dusty and Radiation Pressure Dominated?
• The Radius-Luminosity Relationship Depends on Optical Spectra in Active Galactic Nuclei
• Swift monitoring of NGC 5548: X-ray reprocessing and short term UV/optical variability
• Accretion disk reverberation with Hubble Space Telescope observations of NGC 4593: evidence for diffuse continuum lags
• The Variable Diffuse Continuum Emission of Broad Line Clouds
• Swift monitoring of NGC 4151: Evidence for a Second X-ray/UV Reprocessing
• The origin of the UV/optical lags in NGC 5548
• X-ray/UV/optical variability of NGC 4593 with Swift: Reprocessing of X-rays by an extended reprocessor
• The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-Epoch Spectroscopy
• The Sloan Digital Sky Survey Reverberation Mapping Project: Initial CIV Lag Results from Four Years of Data
• Quantifying the impact of variable BLR diffuse continuum contributions on measured continuum inter-band delays
• Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
• Space Telescope and Optical Reverberation Mapping Project VI: reverberating Disk Models for NGC 5548
• Quantifying the Diffuse Continuum Contribution of BLR Clouds to AGN Continuum Inter-band Delays
• Supermassive black holes with high accretion rates in active galactic nuclei. XI. Accretion disk reverberation mapping of Mrk 142
• Modeling the UV/optical continuum time-lags in AGN
• Application of Stochastic Modeling to Analysis of Photometric Reverberation Mapping Data
• The Sloan Digital Sky Survey Reverberation Mapping Project: MgII Lag Results from Four Years of Monitoring
• Radiation pressure confinement - II. Application to the broad line region in active galactic nuclei
• UV/optical disk thermal reverberation in AGN: an in-depth study with an analytic prescription for the time-lag spectra
• Detection of Time Lags Between Quasar Continuum Emission Bands based on Pan-STARRS Light-curves
• Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies
• Corona-Heated Accretion-disk Reprocessing (CHAR): A Physical Model to Decipher the Melody of AGN UV/optical Twinkling
• Discovery of a ~5 day characteristic timescale in the Kepler power spectrum of Zw 229-15
• On the multi-wavelength variability of Mrk 110: Two components acting at different timescales
• Eleven years of monitoring the Seyfert 1 Mrk 335 with Swift: Characterizing the X-ray and UV/optical variability
• EUCLIA - Exploring the UV/optical continuum lag in active galactic nuclei. I. a model without light echoing
• AGN Continuum Reverberation Mapping Based on Zwicky Transient Facility Light Curves
• Testing broad line region models with Reverberation Mapping
• Non-Blackbody Disks Can Help Explain Inferred AGN Accretion Disk Sizes
• A hard look at thermal reverberation and optical/UV lags in NGC 5548
• Winds Can "Blow Up" AGN Accretion Disk Sizes
• Frequency-resolved lags in UV/optical continuum reverberation mapping
• A physical model for the broadband energy spectrum of X-ray illuminated accretion discs: fitting the spectral energy distribution of NGC 5548
• UV/Optical disk reverberation lags despite a faint X-ray corona in the AGN Mrk 335
• Constraining the dynamical importance of hot gas and radiation pressure in quasar outflows using emission line ratios
• Using AGN lightcurves to map accretion disc temperature fluctuations
• Broad iron emission lines in Seyfert Galaxies - re-condensation of gas onto an inner disk below the ADAF
• Revisiting UV/optical continuum time lags in AGN
• Explaining the moderate UV/X-ray correlation in AGN
• Reconciling the Quasar Microlensing Disc Size Problem with a Wind Model of Active Galactic Nucleus
• A physical model for the UV/optical power spectra of AGN
• The luminosity-dependent contribution from the broad line region to the wavelength-dependent lags in Mrk 110
• Modelling Continuum Reverberation in AGN: A Spectral-Timing Analysis of the UV Variability Through X-ray Reverberation in Fairall 9
• Tracking the year-to-year variation in the spectral energy distribution of the Narrow-line Seyfert 1 Galaxy Mrk335
• Estimating AGN Black Hole Masses via Continuum Reverberation Mapping in the Era of LSST
• A falling Corona model for the anomalous behavior of the broad emission lines in NGC 5548
• AGN STORM 2. VII. A Frequency-resolved Map of the Accretion Disk in Mrk 817: Simultaneous X-ray Reverberation and UVOIR Disk Reprocessing Time Lags
• X-ray/UVOIR Frequency-resolved Time Lag Analysis of Mrk 335 Reveals Accretion Disk Reprocessing
• A Negative Long Lag from the Optical to the UV Continuum in Fairall 9
• The H$\alpha$ broadband photometric reverberation mapping of four Seyfert 1 galaxies
• Robotic reverberation mapping of the broad-line radio galaxy 3C 120
• X-ray, UV, and Radio Timing Observations of the Radio Galaxy 3C 120
• The Host Galaxy Fluxes of Active Galaxy Nuclei Are Generally Overestimated by the Flux Variation Gradient Method