On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei

Abstract

We describe a model-independent method of assessing the uncertainties in cross-correlation lags determined from AGN light curves, and use this method to investigate the reality of lags between UV and optical continuum variations in well-studied AGNs. Our results confirm the existence of such lags in NGC 7469. We find that the continuum variations at 1825 A, 4845 A, and 6962 A follow those at 1315A by 0.22^{+0.12}_{-0.13} days, 1.25^{+0.48}_{-0.35} days, and 1.84^{+0.93}_{-0.94} days, respectively, based on the centroids of the cross-correlation functions; the error intervals quoted correspond to 68% confidence levels, and each of these lags is greater than zero at no less than 97% confidence. We do not find statistically significant interband continuum lags in NGC 5548, NGC 3783, or Fairall 9. Wavelength-dependent continuum lags may be marginally detected in the case of NGC 4151. However, on the basis of theoretical considerations, wavelength-dependent continuum lags in sources other than NGC 7469 are not expected to have been detectable in previous experiments. We also confirm the existence of a statistically significant lag between X-ray and UV continuum variations in the blazar PKS 2155-304.

23 pages, 4 figures. Accepted for publication in PASP

References in corpus (2)

• Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies
• Reverberation Mapping and the Physics of Active Galactic Nuclei

Cited by in corpus (383)

• 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
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei: I. Comparing the Photoionization and Reverberation Techniques
• Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies
• The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta
• Reverberation Mapping of High-Luminosity Quasars: First Results
• Determining Central Black Hole Masses in Distant Active Galaxies
• Keplerian Motion of Broad-Line Region Gas as Evidence for Supermassive Black Holes in Active Galactic Nuclei
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. I. A Reverberation-Based Measurement of the Black Hole Mass
• Generating artificial light curves: Revisited and updated
• Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies
• X-Ray and Optical Variability in NGC 4051 and the Nature of Narrow-Line Seyfert 1 Galaxies
• Multiwavelength Observations of Markarian 421 in March 2001: an Unprecedented View on the X-ray/TeV Correlated Variability
• Optical and radio behaviour of the BL Lacertae object 0716+714
• On the Reliability of Cross Correlation Function Lag Determinations in Active Galactic Nuclei
• The Lick AGN Monitoring Project: Reverberation Mapping of Optical Hydrogen and Helium Recombination Lines
• Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
• The First Swift Intensive AGN Accretion Disk Reverberation Mapping Survey
• Systematic Errors in the Estimation of Black Hole Masses by Reverberation Mapping
• Space Telescope and Optical Reverberation Mapping Project. I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope
• Detection of significant cm to sub-mm band radio and gamma-ray correlated variability in Fermi bright blazars
• Time-correlation between the radio and gamma-ray activity in blazars and the production site of the gamma-ray emission
• Fermi Gamma-ray Space Telescope Observations of Recent Gamma-ray Outbursts from 3C 454.3
• A method for the estimation of the significance of cross-correlations in unevenly sampled red-noise time series
• Swift monitoring of NGC 4151: Evidence for a Second X-ray/UV Reprocessing
• Correlated long-term optical and X-ray variations in NGC 5548
• Simultaneous EUVE/ASCA/RXTE Observations of NGC 5548
• Supermassive black holes with high accretion rates in active galactic nuclei: II. the most luminous standard candles in the Universe
• The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783
• The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT
• The Origin of the X-ray and Ultraviolet Emission in NGC 7469
• Long-Term X-ray Spectral Variability in Seyfert 1 Galaxies
• The Sloan Digital Sky Survey Reverberation Mapping Project: First Broad-line Hbeta and MgII Lags at z>~0.3 from six-Month Spectroscopy
• X-ray/UV/optical variability of NGC 4593 with Swift: Reprocessing of X-rays by an extended reprocessor
• Simultaneous multiwavelength observations of the second exceptional gamma-ray flare of PKS 2155-304 in July 2006
• Modeling reverberation mapping data I: improved geometric and dynamical models and comparison with cross-correlation results
• Characterizing the Gamma-Ray Variability of the Brightest Flat Spectrum Radio Quasars Observed with the Fermi LAT
• The broad emission-line region: the confluence of the outer accretion disc with the inner edge of the dusty torus
• Disk-Jet Connection in the Radio Galaxy 3C 120
• A new direct method for measuring the Hubble constant from reverberating accretion discs in active galaxies
• The first tidal disruption flare in ZTF: from photometric selection to multi-wavelength characterization
• The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-Epoch Spectroscopy
• Spectroscopic Indication for a Centi-parsec Supermassive Black Hole Binary in the Galactic Center of NGC 5548
• Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111
• Limits on an Energy Dependence of the Speed of Light from a Flare of the Active Galaxy PKS 2155-304
• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. III. Detection of Fe II Reverberation in Nine Narrow-Line Seyfert 1 Galaxies
• New constraints on the continuum-emission mechanism of AGN: Intensive monitoring of NGC 7469 in the X-ray and ultraviolet
• Long term optical and X-ray variability of the Seyfert galaxy Markarian 79
• NGC 5548 in a Low-Luminosity State: Implications for the Broad-Line Region
• Correlation and time delays of the X-ray and optical emission of the Seyfert Galaxy NGC3783
• Four Years Monitoring of Blazar PKS 2155-304 with BeppoSAX: Probing the Dynamics of the Jet
• Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
• The Mass of the Central Black Hole in the Seyfert Galaxy NGC 4151
• Reverberation Mapping of Luminous Quasars at High-z
• Highly Accreting Quasars: Sample Definition and Possible Cosmological Implications
• Photometric AGN reverberation mapping - an efficient tool for BLR sizes, black hole masses and host-subtracted AGN luminosities
• Multiwavelength observations of 3C 454.3. III. Eighteen months of AGILE monitoring of the "Crazy Diamond"
• Velocity-resolved reverberation mapping of five bright Seyfert 1 galaxies
• Rapid X-ray Variability of the BL Lacertae Object PKS 2155-304
• Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469
• Broad-Line Reverberation in the Kepler-Field Seyfert Galaxy Zw 229-015
• Quasar Accretion Disk Sizes From Continuum Reverberation Mapping From the Dark Energy Survey
• Comparing the spectral lag of short and long gamma-ray bursts and its relation with the luminosity
• Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548
• Variability Time Scales of TeV Blazars Observed in the ASCA Continuous Long-Look X-ray Monitoring
• The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005
• Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71, III. Rapid and correlated flux density variability from radio to sub-mm bands
• WISDOM Project - II: Molecular gas measurement of the supermassive black hole mass in NGC4697
• Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous behavior of the broad ultraviolet emission lines in NGC 5548
• First Results from the Lick AGN Monitoring Project: The Mass of the Black Hole in Arp 151
• X-ray Emission of Mkn 421: New Clues From Its Spectral Evolution. I. Temporal Analysis
• Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Akn 564. I. ASCA Observations and the Variability of the X-ray Spectral Components
• A 10,000-solar-mass black hole in the nucleus of a bulgeless dwarf galaxy
• A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151
• Detection of Time Lags Between Quasar Continuum Emission Bands based on Pan-STARRS Light-curves
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. III. Characterisation of total flux density and polarisation variability of relativistic jets
• The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability
• Corona-Heated Accretion-disk Reprocessing (CHAR): A Physical Model to Decipher the Melody of AGN UV/optical Twinkling
• Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment
• The long-lasting activity of 3C 454.3. GASP-WEBT and satellite observations in 2008-2010
• The UV peak in Active Galactic Nuclei : a false continuum from blurred reflection ?
• Intensive HST, RXTE and ASCA Monitoring of NGC 3516: Evidence Against Thermal Reprocessing
• Broad-Band Spectral Energy Distributions of Active Galactic Nuclei from an Accretion Disk with Advective Coronal Flow
• Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Akn 564. II. Ultraviolet Continuum and Emission-line Variability
• Reverberation Mapping of the Broad-line Region in NGC 5548: Evidence for Radiation Pressure?
• Complex Optical-X-ray Correlations in the Narrow-Line Seyfert 1 Galaxy NGC 4051
• Ultraviolet and X-ray variability of active galactic nuclei with Swift
• Optical Monitoring of BL Lacertae Object S5 0716+714 with a Novel Multi-Peak Interference Filter
• An investigation of the origin of soft X-ray excess emission from Narrow-line Seyfert 1 galaxies Akn564 and Mrk1044
• Robust Constraint on Lorentz Violation Using Fermi-LAT Gamma-Ray Burst Data
• Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Akn 564. III. Optical Observations and the Optical--UV--X-ray Connection
• Multi-band optical micro-variability observations of BL Lacertae
• The mass of the black hole in 3C 273
• Structure and flux variability in the VLBI jet of BL Lacertae during the WEBT campaigns (1995--2004)
• Optical Monitoring of the Broad-Line Radio Galaxy 3C390.3
• Multiwavelength Cross-Correlations and Flaring Activity in Bright Blazars
• The core shift effect in the blazar 3C 454.3
• Quasar Accretion Disk Sizes from Continuum Reverberation Mapping in the DES Standard Star Fields
• Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies
• The first Fermi multifrequency campaign on BL Lacertae: characterizing the low-activity state of the eponymous blazar
• A connection between $\gamma$-ray and parsec-scale radio flares in the blazar 3C 273
• Short-term emission line and continuum variations in Mrk110
• Reverberation Measurements of the Inner Radii of the Dust Tori in Quasars
• Locating the gamma-ray emission site in Fermi/LAT blazars from correlation analysis between 37 GHz radio and gamma-ray light curves
• X-ray and radio variability in the low luminosity Active Galactic Nucleus NGC 7213
• Radio-to-UV monitoring of AO 0235+164 by the WEBT and Swift during the 2006--2007 outburst
• Black Hole Masses in Three Seyfert Galaxies
• Temporal characteristics of the X-ray emission of NGC 7469
• The long-term optical spectral variability of BL Lacertae
• Accretion Disk Sizes from Continuum Reverberation Mapping of AGN Selected from the ZTF Survey
• AGN Continuum Reverberation Mapping Based on Zwicky Transient Facility Light Curves
• EUCLIA - Exploring the UV/optical continuum lag in active galactic nuclei. I. a model without light echoing
• The Mass of the Black Hole in the Quasar PG 2130+099
• Broad Band Photometric Reverberation Mapping of NGC 4395
• Fermi-LAT Detection of Gravitational Lens Delayed Gamma-ray Flares from Blazar B0218+357
• Spikey: Self-Lensing Flares from Eccentric SMBH Binaries
• A Comprehensive X-ray Spectral Analysis of the Seyfert 1.5 NGC 3227
• Spin period evolution of GX 1+4
• A High Signal-to-Noise UV Spectrum of NGC 7469: New Support for Reprocessing of Continuum Radiation
• CIV Black Hole Mass Measurements with the Australian Dark Energy Survey (OzDES)
• Time delay measurement of Mg II line in CTS C30.10 with SALT
• Photometric reverberation mapping of 3C120
• The Mass of the Central Black Hole in the Nearby Seyfert Galaxy NGC5273
• Unusual Central Engine Activity in the Double Burst GRB 110709B
• Long-term monitoring of the archetype Seyfert galaxy MCG-6-30-15: X-ray, optical and near-IR variability of the corona, disc and torus
• Multiwavelength behaviour of the blazar 3C279: decade-long study from $\gamma$-ray to radio
• XMM-Newton view of PKS 2155-304: hardness ratio and cross-correlation analysis of EPIC pn observations
• A Reverberation-Based Black Hole Mass for MCG-06-30-15
• The molecular gas content in obscured AGN at z > 1
• Rehabilitating CIV-based black hole mass estimates in quasars
• Evidence for variability timescale dependent UV/X-ray delay in Seyfert 1 AGN NGC 7469
• Photometric Reverberation Mapping of the Broad Emission Line Region in Quasars
• Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations
• On Reverberation Mapping Lag Uncertainties
• BLR kinematics and Black Hole Mass in Markarian 6
• Dust Reverberation Mapping in Distant Quasars from Optical and Mid-Infrared Imaging Surveys
• Cross-spectral analysis of the X-ray variability of Mrk 421
• Time Delay of MgII Emission Response for the Luminous Quasar HE 0435-4312: Towards Application of High-Accretor Radius-Luminosity Relation in Cosmology
• Monitoring AGNs with H$\beta$ Asymmetry. III. Long-term Reverberation Mapping Results of 15 Palomar-Green Quasars
• Simultaneous B'V'R' Monitoring of BL Lacertae Object S5~0716+714 and Detection of Inter-Band Time Delay
• Determination of the Central Mass in Active Galactic Nuclei Using Cross-Correlation Lags and Velocity Dispersions
• High Temporal Resolution XMM Monitoring of PKS 2155-304
• Multiwavelength observations of 3C 454.3 II. The AGILE 2007 December campaign
• Correlated X-ray/Ultraviolet/Optical Variability in NGC 6814
• Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation
• XMM - Newton observations of Markarian 421
• The picture of BLR in 2.5-D FRADO: Dynamics & Geometry
• Monitoring of the optical and 2.5-11.7 micron spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk279 with ISO
• Winds Can "Blow Up" AGN Accretion Disk Sizes
• Accretion Disk Size Measurements of Active Galactic Nuclei Monitored by the Zwicky Transient Facility
• The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65
• Simulating the timescale dependent color variation in quasars with a revised inhomogeneous disk model
• Constraints on the broad line region from regularized linear inversion: Velocity-delay maps for five nearby active galactic nuclei
• Multiwavelength behaviour of the blazar OJ 248 from radio to γ-rays
• Current and future applications of Reverberation-mapped quasars in Cosmology
• On the size of the Fe II emitting region in the AGN Akn 120
• X-ray and Optical Correlation of Type I Seyfert NGC 3516 Studied with Suzaku and Japanese Ground-Based Telescopes
• The Sloan Digital Sky Survey Reverberation Mapping Project: Comparison of Lag Measurement Methods with Simulated Observations
• Variability of accretion flow in the core of the Seyfert galaxy NGC 4151
• OzDES Reverberation Mapping Program: The first Mg II lags from five years of monitoring
• Variability and Proper Motion of X-ray Knots in the Jet of Centaurus A
• HST FOC spectroscopy of the NLR of NGC 4151. I. Gas kinematics
• Reverberation mapping of narrow-line Seyfert 1 galaxy I Zwicky 1: black hole mass
• Imbalance Learning for Variable Star Classification
• Cosmology with AGN dust time lags -- Simulating the new VEILS survey
• Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC~4151 During Outburst Stage: Evidence for Kinematics Evolution of Broad-line Region
• Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and $\gamma$-ray activity in 2015$-$2016
• Disentangling the synchrotron and Inverse Compton variability in the X-ray emission of the intermediate BL Lac object S5 0716+71
• Bayesian Analysis of Quasar Lightcurves with a Running Optimal Average: New Time Delay Measurements of COSMOGRAIL Gravitationally Lensed Quasars
• Cosmic neutrinos from temporarily gamma-suppressed blazars
• Bivariate phase-rectified signal averaging
• Evidence for Two Distinct Broad-Line Regions from Reverberation Mapping of PG 0026+129
• Spitzer Space Telescope Measurements of Dust Reverberation Lags in the Seyfert 1 Galaxy NGC 6418
• Implications of the X-ray Variability for the Mass of MCG-6-30-15
• Discovery of Polarization Reverberation in NGC 4151
• 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
• Quasar Cartography: from Black Hole to Broad Line Region Scales
• X-ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783
• Multi-Wavelength Monitoring and Reverberation Mapping of a Changing Look Event in the Seyfert Galaxy NGC 3516
• Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns. I. Evolution of structure and kinematics
• Complex X-ray spectral variability in Mkn 421 observed with XMM-Newton
• On the nature of the hard X-ray sources SWIFTJ1907.3-2050, IGRJ12123-5802 and IGRJ19552+0044
• Multi-band optical-NIR variability of blazars on diverse timescales
• WISE view of changing-look AGNs: evidence for a transitional stage of AGNs
• Explaining the moderate UV/X-ray correlation in AGN
• A High-Quality velocity-delay map of the broad-line region in NGC 5548
• Multiple Regression Analysis of the Variable Component in the Near-Infrared Region for Type 1 AGN MCG+08-11-011
• A Low-Mass Black Hole in the Nearby Seyfert Galaxy UGC 06728
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. III. Optical Variability and X-ray/UV/Optical Correlations
• EUCLIA. II. On the puzzling large UV to X-ray lags in Seyfert galaxies
• X-ray to UV Variability Correlation in MCG-6-30-15
• A multi-epoch spectroscopic study of the BAL quasar APM 08279+5255 II. Emission- and absorption-line variability time lags
• The extreme blazar AO 0235+164 as seen by extensive ground and space radio observations
• Size and disk-like shape of the broad-line region of ESO399-IG20
• Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013-2017
• The Changing Look Blazar B2 1420+32
• Broad-line Region of the Quasar PG 2130+099 from a Two-Year Reverberation Mapping Campaign with High Cadence
• The Dusty Heart of NGC 4151 Revealed by $\lambda \sim$1-40 $\mu$m Reverberation Mapping and Variability: A Challenge to Current Clumpy Torus Models
• What can the 2008/10 broadband flare of PKS 1502+106 tell us? Nuclear opacity, magnetic fields, and the location of gamma rays
• Locating the gamma-ray emission site in Fermi/LAT blazars. II Multifrequency correlations
• Reverberation Mapping of IC4329A
• Methods of Reverberation Mapping. I. Time-lag Determination by Measures of Randomness
• Long-term and multi-wavelength evolution of a changing-look AGN Mrk 1018
• Active Galactic Nuclei with Ultra-fast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind
• Scatter Analysis Along the Multidimensional Radius-Luminosity Relations for Reverberation-Mapped Mg II Sources
• Balmer and He I absorption in the nuclear spectrum of NGC 4151
• Radio-Gamma-ray connection and spectral evolution in 4C +49.22 (S4 1150+49): the Fermi, Swift and Planck view
• Broad line region and black hole mass of PKS 1510-089 from spectroscopic reverberation mapping
• Dust reverberation mapping in the era of big optical surveys and its cosmological application
• Strong Soft X-ray Excess in 2015 XMM-Newton Observation of BL--Lac OJ~287
• Doppler speeds of the hydrogen Lyman lines in solar flares from EVE
• Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring
• Simultaneous H alpha and dust reverberation mapping of 3C120: Testing the bowl-shaped torus geometry
• MOMO VI: Multifrequency radio variability of the blazar OJ 287 from 2015-2022, absence of predicted 2021 precursor-flare activity, and a new binary interpretation of the 2016/2017 outburst
• Intraday Optical Variability of BL Lacertae
• Long-term monitoring of PKS0558-504 with Swift: the disc-corona link
• Gaia Data Release 3: The first Gaia catalogue of variable AGN
• A deep X-ray view of the bare AGN Ark 120. III. X-ray timing analysis and multiwavelength variability
• Curvature induced polarization and spectral index behavior for PKS 1502+106
• Modelling Continuum Reverberation in AGN: A Spectral-Timing Analysis of the UV Variability Through X-ray Reverberation in Fairall 9
• Multiwavelength Observations of the BL Lacertae Object PKS 2155-304 with XMM-Newton
• Long term optical and infrared variability characteristics of Fermi Blazars
• A revised lens time delay for JVAS B0218+357 from a reanalysis of VLA monitoring data
• Robotic Reverberation Mapping of the Southern Seyfert NGC 3783
• Expectations for time-delay measurements in active galactic nuclei with the Vera Rubin Observatory
• X-ray, UV and optical time delays in the bright Seyfert galaxy Ark 120 with co-ordinated Swift and ground-based observations
• Estimating AGN Black Hole Masses via Continuum Reverberation Mapping in the Era of LSST
• Multi-band Variability of the TeV Blazar PG 1553+113 with XMM-Newton
• Reverberation Mapping of the Intermediate Mass Nuclear Black Hole in SDSS J114008.71+030711.4
• Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales
• Multi-wavelength Variability of the Broad Line Radio Galaxy 3C 120
• Limits on quantum gravity effects from Swift short gamma-ray bursts
• Short-Timescale monitoring of the X-ray, UV and broad double-peak emission line of the nucleus of NGC 1097
• Optical and Radio Variability of BL Lacertae
• Optical Continuum Reverberation in the Dwarf Seyfert Nucleus of NGC 4395
• An active state of the BL Lac Object Markarian 421 detected by INTEGRAL in April 2013
• The relentless variability of Mrk 421 from the TeV to the radio
• A comprehensive study on the variation phenomena of AO 0235+164
• Simultaneous optical monitoring of BL Lacertae object S5 0716+714 with high temporal resolution
• Timing and Spectral Analysis of the Unusual X-Ray Transient XTE J0421+560/CI Camelopardalis
• The black hole mass of the $z=2.805$ multiply imaged quasar SDSS J2222+2745 from velocity-resolved time lags of the CIV emission line
• Interpreting broad emission-line variations II: Tensions between luminosity, characteristic size and responsivity
• Testing Super-Eddington Accretion onto a Supermassive Black Hole: Reverberation Mapping of PG 1119+120
• Statistical Time-Resolved Spectroscopy: A higher fraction of short-period binaries for metal-rich F-type dwarfs in SDSS
• 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
• Dust Reverberation of 3C273: torus structure and lag -- luminosity relation
• A 12-day ASCA Observation of the Narrow-Line Seyfert 1 Galaxy Ton S180: Time-Selected Spectroscopy
• H$\alpha$ Reverberation Mapping of the Intermediate-Mass Active Galactic Nucleus in NGC 4395
• AGN STORM 2. III. A NICER view of the variable X-ray obscurer in Mrk 817
• Long-term monitoring of Ark 120 with Swift
• The Nearest Neutron Star Candidate in a Binary Revealed by Optical Time-domain Surveys
• Improving the Flux Calibration in Reverberation Mapping by Spectral Fitting: Application to the Seyfert Galaxy MCG--6-30-15
• Narrow Fe-K$\alpha$ Reverberation Mapping Unveils the Deactivated Broad-Line Region in a Changing-Look Active Galactic Nucleus
• Twisted quasar light curves: implications for continuum reverberation mapping of accretion disks
• Multi-wavelength Observations of Sgr A*. I. 2019 July 18
• Mid-infrared Variability of Low-redshift Active Galactic Nuclei : Constraints on a Hot Dust Component with a Variable Covering Factor
• On the UV/optical variation in NGC 5548: new evidence against the reprocessing diagram
• A Negative Long Lag from the Optical to the UV Continuum in Fairall 9
• Variability and the size-luminosity relation of the intermediate mass AGN in NGC 4395
• X-ray/UVOIR Frequency-resolved Time Lag Analysis of Mrk 335 Reveals Accretion Disk Reprocessing
• The rare X-ray flaring activity of the Ultraluminous X-ray source NGC 4559 X7
• Spectral components in the bright, long GRB 061007: properties of the photosphere and the nature of the outflow
• Constraints on accretion disk size in the massive type 1 quasar PG 2308+098 from optical continuum reverberation lags
• OzDES Reverberation Mapping Program: Lag recovery reliability for 6-year CIV analysis
• Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping
• Multi-band optical micro-variability observations of the BL Lac object S4 0954+658
• 3C390.3: More Stable Evidence for Origination of Double-Peaked Broad Balmer Lines from Accretion Disk Near Central Black Hole
• Anomalous Broad-Line Region Responses to Continuum Variability in Active Galactic Nuclei. I. H$\beta$ Variability
• Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926
• MAXI J1820+070 with NuSTAR II. Flaring during the hard to soft state transition with a long soft lag
• Detection of periodic signals in AGN red noise light curves: empirical tests on the Auto-Correlation Function and Phase Dispersion Minimization
• Interferometric Monitoring of Gamma-ray Bright AGNs: OJ 287
• Estimating Masses of Supermassive Black Holes in Active Galactic Nuclei from the Halpha Emission Line
• The variability of blazars throughout the electromagnetic spectrum
• Time delays between Fermi LAT and GBM light curves of GRBs
• Time-lag between disk and corona radiation leads to hysteresis effect observed in black-hole X-ray binary MAXI J1348-630
• Contrasting X-ray/UV time-lags in Seyfert 1 galaxies NGC 4593 and NGC 7469 using AstroSat observations
• Continuum reverberation mapping of the quasar PG 2130+099
• Interferometric Monitoring of Gamma-ray Bright AGNs: S5 0716+714
• Long-term multi-wavelength study of 1ES 0647+250
• The Effects of Periodically Gapped Time Series on Cross-correlation Lag Determinations
• Light-Curve Structure and Halpha Line Formation in the Tidal Disruption Event AT 2019azh
• Rapid X-ray Variability in Mkn 421 during a Multiwavelength Campaign
• Intra-day optical multi-band quasi-simultaneous observation of BL Lacertae object S5 0716+714 from 2013 to 2016
• Interferometric Monitoring of Gamma-ray Bright AGNs: Measuring the Magnetic Field Strength of 4C +29.45
• A Tentative Size-Luminosity Relation for the Iron Emission-Line Region in Quasars
• Estimation of the size and structure of the broad line region using Bayesian approach
• Joint ALMA/X-ray monitoring of the radio-quiet type 1 AGN IC 4329A
• Wavelength-resolved reverberation mapping of intermediate redshift quasars HE 0413-4031 and HE 0435-4312: Dissecting Mg II, optical Fe II, and UV Fe II emission regions
• The study of multi-peaked type-I X-ray bursts in the neutron-star low mass X-ray binary 4U 1636$-$536 with RXTE
• Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514
• Reverberation-mapping of distant quasars: time-lag determination using different methods
• UV to X-ray Comptonization delay in Mrk 493
• Locations of optical and $\gamma$-ray emitting regions in the jet of PMN J2345-1555
• Wavelength-resolved Reverberation Mapping of quasar CTSC30.10: Dissecting MgII and FeII emission regions
• Unusual Flaring Activity in the Blazar PKS 1424-418 during 2008-2011
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. II. X-ray and Ultraviolet Continuum Variability
• A highly variable methanol maser in G111.256-0.770
• Spectral variability of the 3C 390.3 nucleus for more than twenty years. I. Variability of the broad and narrow emission-line fluxes
• Continuum reverberation mapping of MCG 08-11-011
• Interpreting the variation phenomena of B2 1633+382 via the two-component model
• Emission Line Variability during a Nonthermal Outburst in the Gamma-Ray Bright Quasar 1156+295
• Constraints on the composition, magnetization, and radiative efficiency in jet of blazar
• Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26
• AGN Light Echoes and the Accretion Disc Self-Gravity Limit
• Time-resolved spectroscopy on the heartbeat state of GRS 1915+105 using AstroSat
• Dust Reverberation Mapping of Z229-15
• BLR size in Realistic FRADO Model: The role of shielding effect
• X-ray, UV, and Radio Timing Observations of the Radio Galaxy 3C 120
• Robotic reverberation mapping of the broad-line radio galaxy 3C 120
• Complex UV/X-ray variability of 1H~0707-495
• A possible overall scenario for the outburst evolution of MAXI J1820+070 revealed by Insight-HXMT
• Long-term multi-band photometric monitoring of Mrk 501
• Dust Reverberation Mapping of Type 2 AGN NGC 2110 Realized with X-ray and 3-5 $\mu$m IR monitoring
• Variability of NGC 4051 and the Nature of Narrow-Line Seyfert 1 Galaxies
• Constraining broad-line regions from time lags of broad emission lines relative to radio emission
• Multi-wavelength Variation Phenomena of PKS 0735+178 on Diverse Timescale
• Connecting the X-ray/UV variability of Fairall 9 with NICER: A Possible Warm Corona
• Introducing the Condor Array Telescope: III. The expansion and age of the shell of the dwarf nova Z Camelopardalis, and detection of a second, larger shell
• Modulations of the Surface Magnetic Field on the Intra-cycle Variability of Total Solar Irradiance
• Correlation between Line Width and Line Flux of Double-Peaked Broad Halpha of 3C390.3
• UV Fe II emission model of HE 0413-4031 and its relation to broad-line time delays
• A fast test for the identification and confirmation of massive black hole binaries
• The Correlated Multi-color Optical Variations of BL Lac Object S5 0716+714
• Complex optical/UV and X-ray variability in Seyfert 1 galaxy Mrk 509
• AT2018fyk: Candidate Tidal Disruption Event by a (Super)massive Black Hole Binary
• Thermal Comptonization and Disk Thermal Reprocessing in NGC 3516
• Detection of X-ray/UV delay in NGC 4051 using AstroSat observations
• Detection of a 20 minute time lag observed from Sgr A* between 8 and 10 GHz with the VLA
• A Spectroscopic and Photometric Study of Short-Timescale Variability in NGC5548
• Gamma-ray flares and broadband spectral study of PKS 0402-362
• Analysis of the intra-night variability of BL Lacertae during its August 2020 flare
• Correlated Short-Timescale Hard-Soft X-ray Variability of the Blazars Mrk 421 and 1ES 1959+650 using $\text{AstroSat}$
• Velocity-Resolved Ionization Mapping of Broad Line Region. I. Insights into Diverse Geometry and Kinematics
• A Gaussian process cross-correlation approach to time delay estimation in active galactic nuclei
• Spectral Evolution of Ultraluminous X-ray Pulsar NGC 300 ULX-1
• Intra-day variability of BL Lacertae from 2016 to 2018
• Changing look AGN Mrk 590: Broad line region and black hole mass from photometric reverberation mapping
• Spectral variability of the 3C 390.3 nucleus for more than 20 years -- II. Variability of the broad emission-line profiles and He II $\lambda 4686$A emission-line fluxes
• Chromatic Microlensing Time Delays
• Mass of the black hole in the Seyfert 1.5 galaxy H 0507+164 from reverberation mapping
• The spatial distribution of circumstellar material of the wind-fed system GX 301-2
• Detection of disk-jet co-precession in a tidal disruption event
• Testing compact massive black hole binary candidates through multi-epoch spectroscopy
• A Search for X-ray/UV Correlation in the Reflection-Dominated Seyfert 1 Galaxy Mrk 1044
• Multiwavelength campaign on Mrk 509. XVI. Continued HST/COS monitoring of the far-ultraviolet spectrum
• Observational window effects on multi-object Reverberation Mapping
• Diagnostics of the structure of AGN's broad line regions with reverberation mapping data: confirmation of the two-component broad line region model
• Coexistence of Chromatic Flares and an Achromatic QPO in the Gamma-ray Blazar PG 1553+113
• Long-term multi-wavelength variations of Fermi blazar 3C 279
• Dust Reverberation Mapping and Light-Curve Modelling of Zw229-015
• Revisiting Correlations Between Broad-Line and Jet Emission Variations for AGNs: 3C 120 and 3C 273
• H$\beta$ line shape and radius-luminosity relation in 2.5D FRADO
• Detection of highly correlated optical and X-ray variations in SS Cygni with Tomo-e Gozen and NICER
• Polarization Studies in Different Blazar Types. Part I: Correlation between Optical Brightness and Polarization Degree
• On reverberation and cross-correlation estimates of the size of the broad-line region in active galactic nuclei
• Timescale-dependent X-ray to UV time lags of NGC 4593 using high-intensity XMM-Newton observations with Swift and AstroSat
• A Soft X-Ray Lag Detected in Centaurus A
• Long term Ultra-Violet Variability of Seyfert galaxies
• Testing X-ray Reprocessing and Mapping the Soft Excess of NGC 7469 with NICER
• Revisiting the Continuum Reverberation Lags in the AGN PKS 0558-504
• Hints of correlation between broad-line and radio variations for 3C 120
• HALO I: Photometric continuum reverberation mapping of Fairall 9
• Scalable and Robust Multiband Modeling of AGN Light Curves in Rubin-LSST
• OzDES Reverberation Mapping Program: Stacking analysis with H$\beta$, Mg II and C IV
• Long Term Reverberation Mapping of Iron Coronal Lines in MKN 110
• Can a time evolving, asymmetric broad line region mimic a massive black hole binary?
• Relentless multi-wavelength variability of Mrk 421 and Mrk 501
• Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018
• Intensive X-ray/UVOIR continuum reverberation mapping of the Seyfert AGN MCG+08-11-11
• Strong X-ray Variability of I Zwicky 1: Obscuration from Clumpy Accretion-Disk Winds
• Multi-wavelength variability analysis of the blazar S5 0716+714 during a long-lasting period of low activity
• Time domain astrophysics with transient sources. Delay estimate via Cross Correlation Function techniques
• High energy time lags of Gamma Ray Bursts
• Pinpointing the location of the gamma-ray emitting region in the FSRQ 4C+01.28
• Flux Variations of Fast Radio Bursts and Their Persistent Radio Sources: Evidence for a Shared Progenitor
• Near-infrared spectroscopy of extreme BAL QSOs from the QUBRICS bright quasar survey
• Non-thermal emission from fall-back clouds in the Broad-Line Region of Active Galactic Nuclei
• Reverberation Mapping of Two Luminous Quasars: the Broad-line Region Structure and Black Hole Mass
• X-ray Fourier lag-frequency spectra modulated by stochastic turbulent acceleration in the jets of high-frequency-peaked BL Lac