Untangling the Complex Nature of AGN Variability with Fairall 9

Abstract

The accretion flow in AGN is not well understood, motivating intensive monitoring campaigns of multiwavelength variability to probe its structure. One of the best of these is the 3 year optical/UV/X-ray approximately daily monitoring campaign on Fairall\,9, a fairly typical moderate accretion rate AGN. The UV lightcurve shows a clear increase over $\sim 50$ days between years 1 and 2, strongly coherent with the X-ray lightcurve rise. This changes the average spectral energy distribution such that the disc component is stronger while the X-ray spectrum steepens, so that the total X-ray power remains roughly constant. Outside of this global change, we apply a Fourier resolved analysis to test stochastic models where intrinsic fluctuations in the UV disc propagate down into the hard X-ray emission region via both changing the seed photon flux for Compton scattering (short light travel timescale) and changing the electron density (longer propagation timescale). Unlike these models, the hard X-rays are not particularly well correlated with the UV, and also have the wrong sign in that the hard X-rays marginally lead the UV fluctuations. We show that this is instead consistent with uncorrelated stochastic fluctuations in both the UV (slow) and X-ray (fast), which are linked together only weakly via light travel time. These variability properties, as well as the changes in the SED, has implications for our understanding of AGN structure and physics, as well as future monitoring campaigns.

17 pages, 8 figures, Submitted to MNRAS after addressing initial round of referee comments. Comments welcome

References in corpus (99)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
• Modelling the behaviour of accretion flows in X-ray binaries
• Photometric Calibration of the Swift Ultraviolet/Optical Telescope
• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Active Galactic Nuclei as scaled-up Galactic black holes
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• Intrinsic disc emission and the Soft X-ray Excess in AGN
• Going with the flow: can the base of jets subsume the role of compact accretion disk coronae?
• The Soft X-Ray Properties of a Complete Sample of Optically Selected Quasars II. Final Results
• An Explanation for the soft X-ray excess in AGN
• X-ray reverberation around accreting black holes
• Measuring the broadband power spectra of active galactic nuclei with RXTE
• Investigating a Fluctuating-accretion Model for the Spectral-timing Properties of Accreting Black Hole Systems
• Ubiquitous equatorial accretion disc winds in black hole soft states
• Combined Long and Short Timescale X-ray Variability of NGC4051 with RXTE and XMM-Newton
• The AGN Black Hole Mass Database
• A Model for the X-Ray and UV Emission from Seyfert Galaxies and Galactic Black Holes
• 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
• The corona contracts in a black-hole transient
• X-ray Fluctuation Power Spectral Densities of Seyfert 1 Galaxies
• X-Ray Variability Coherence: How to Compute it, What it Means, and How it Constrains Models of Cyg X-1 and GX 339-4
• XMM-Newton EPIC observations of 21 low-redshift PG quasars
• A physical model of the broadband continuum of AGN and its implications for the UV/X relation and optical variability
• A global look at X-ray time lags in Seyfert Galaxies
• Explaining changing-look AGN with state transition triggered by rapid mass accretion rate drop
• CAIXA: a catalogue of AGN in the XMM-Newton archive III. Excess Variance Analysis
• The tight relation between X-ray and ultraviolet luminosity of quasars
• A physical model for the continuum variability and QPO in accreting black holes
• The First Swift Intensive AGN Accretion Disk Reverberation Mapping Survey
• Testing warm Comptonization models for the origin of the soft X-ray excess in AGN
• Anatomy of the AGN in NGC 5548: I. A global model for the broadband spectral energy distribution
• A Cutoff in the X-ray Fluctuation Power Density Spectrum of the Seyfert 1 Galaxy NGC 3516
• Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
• 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
• Multiwavelength campaign on Mrk 509. IV. Optical-UV-X-ray variability and the nature of the soft X-ray excess
• Swift monitoring of NGC 4151: Evidence for a Second X-ray/UV Reprocessing
• An exact analytic treatment of propagating mass accretion rate fluctuations in X-ray binaries
• Correlated long-term optical and X-ray variations in NGC 5548
• Multiwavelength campaign on Mrk 509 XII. Broad band spectral analysis
• Modelling variability in black hole binaries: linking simulations to observations
• The origin of the UV/optical lags in NGC 5548
• Discovery of high-frequency iron K lags in Ark 564 and Mrk 335
• X-ray/UV/optical variability of NGC 4593 with Swift: Reprocessing of X-rays by an extended reprocessor
• Evaporation of accretion disks around black holes: the disk-corona transition and the connection to the advection-dominated accretion flow
• Correlated X-ray/Optical Variability in the Quasar MR2251-178
• The Analogous Structure of Accretion Flows in Supermassive and Stellar Mass Black Holes: New Insights from Faded Changing-Look Quasars
• A new direct method for measuring the Hubble constant from reverberating accretion discs in active galaxies
• Quasar Viscosity Crisis
• Line driven winds and the UV turnover in AGN accretion discs
• Quantifying the impact of variable BLR diffuse continuum contributions on measured continuum inter-band delays
• Long term optical and X-ray variability of the Seyfert galaxy Markarian 79
• Correlation and time delays of the X-ray and optical emission of the Seyfert Galaxy NGC3783
• Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
• The Closest Look at 1H0707-495: X-ray Reverberation Lags with 1.3 Ms of Data
• Modeling the UV/optical continuum time-lags in AGN
• Uncovering the geometry of the hot X-ray corona in the Seyfert galaxy NGC4151 with IXPE
• The existence of warm and optically thick dissipative coronae above accretion disks
• UV/optical disk thermal reverberation in AGN: an in-depth study with an analytic prescription for the time-lag spectra
• Spectral variability and reverberation time delays in the Suzaku X-ray spectrum of NGC 4051
• Discovery of Fe K-alpha X-ray reverberation around the black holes in MCG-5-23-16 and NGC 7314
• On the multi-wavelength variability of Mrk 110: Two components acting at different timescales
• Two-phase radiative/conductive equilibrium in AGN and GBH
• A wind-based unification model for NGC 5548: spectral holidays, non-disk emission, and implications for changing-look quasars
• EUCLIA - Exploring the UV/optical continuum lag in active galactic nuclei. I. a model without light echoing
• Opacity Driven Convection and Variability in Accretion Disks around Supermassive Black Holes
• The flux-dependent X-ray time lags in NGC 4051
• Calculating Time Lags From Unevenly-Sampled Light Curves
• BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
• The rhythm of Fairall 9 -- I: Observing the spectral variability with XMM-Newton and NuSTAR
• Using AGN lightcurves to map accretion disc temperature fluctuations
• Low frequency X-ray timing with Gaussian processes and reverberation in the radio-loud AGN 3C 120
• Explaining the moderate UV/X-ray correlation in AGN
• Statistical properties of Fourier-based time-lag estimates
• EUCLIA. II. On the puzzling large UV to X-ray lags in Seyfert galaxies
• reXcor: A Model of the X-ray Spectrum of Active Galactic Nuclei that Combines Ionized Reflection and a Warm Corona
• A physical model for the UV/optical power spectra of AGN
• A universal average spectral energy distribution for quasars from optical to extreme ultraviolet
• Modelling the Multiwavelength Variability of Mrk 335 using Gaussian Processes
• Modelling Continuum Reverberation in AGN: A Spectral-Timing Analysis of the UV Variability Through X-ray Reverberation in Fairall 9
• Discarding the disc in a changing state AGN: the UV/X-ray relation in NGC 4151
• X-ray Reverberation Mapping of Ark 564 using Gaussian Process Regression
• 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
• BASS-XL: X-ray variability properties of unobscured Active Galactic Nuclei
• Broadband X-ray/UV/optical time-resolved spectroscopy of NGC 5548: The origin of the UV/optical variability in active galactic nuclei
• Connecting the X-ray/UV variability of Fairall 9 with NICER: A Possible Warm Corona
• Constraining Energy-dependent emissivity profiles of AGN inflows