Bayesian Analysis of Quasar Lightcurves with a Running Optimal Average: New Time Delay Measurements of COSMOGRAIL Gravitationally Lensed Quasars

Abstract

We present a new method of modelling time-series data based on the running optimal average (ROA). By identifying the effective number of parameters for the ROA model, in terms of the shape and width of its window function and the times and accuracies of the data, we enable a Bayesian analysis, optimising the ROA width, along with other model parameters, by minimising the Bayesian Information Criterion (BIC) and sampling joint posterior parameter distributions using MCMC methods. For analysis of quasar lightcurves, our implementation of ROA modelling can measure time delays among lightcurves at different wavelengths or from different images of a lensed quasar and, in future work, be used to inter-calibrate lightcurve data from different telescopes and estimate the shape and thus the power-density spectrum of the lightcurve. Our noise model implements a robust treatment of outliers and error-bar adjustments to account for additional variance or poorly-quantified uncertainties. Tests with simulated data validate the parameter uncertainty estimates. We compare ROA delay measurements with results from cross-correlation and from JAVELIN, which models lightcurves with a prior on the power-density spectrum. We analyse published COSMOGRAIL lightcurves of multi-lensed quasar lightcurves and present the resulting measurements of the inter-image time delays and detection of microlensing effects.

arXiv commentAccepted for publication in MNRAS

References in corpus (44)

• emcee: The MCMC Hammer
• Planck 2015 results. XIII. Cosmological parameters
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Observational Evidence of AGN Feedback
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Las Cumbres Observatory Global Telescope Network
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• Quantifying Quasar Variability As Part of a General Approach To Classifying Continuously Varying Sources
• An Alternative Approach To Measuring Reverberation Lags in Active Galactic Nuclei
• Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broad-Band Time Delays in NGC 5548
• Testing thermal reprocessing in AGN accretion discs
• Spatially resolved rotation of the broad-line region of a quasar at sub-parsec scale
• The Sloan Digital Sky Survey Reverberation Mapping Project: H$\alpha$ and H$\beta$ Reverberation Measurements From First-year Spectroscopy and Photometry
• Optical Variability in Active Galactic Nuclei: Starbursts or Disk Instabilities?
• Reverberation mapping of Active Galactic Nuclei: from X-ray corona to dusty torus
• Quasar Accretion Disks Are Strongly Inhomogeneous
• The Sloan Digital Sky Survey Reverberation Mapping Project: Technical Overview
• The First Swift Intensive AGN Accretion Disk Reverberation Mapping Survey
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XI. Techniques for time delay measurement in presence of microlensing
• A quadruply imaged quasar with an optical Einstein ring candidate: 1RXS J113155.4-123155
• COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408-5354 with high-cadence photometric monitoring
• Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
• HE 0435-1223: a wide separation quadruple QSO and gravitational lens
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses I. How to sample the light curves of gravitationally lensed quasars to measure accurate time delays
• COSMOGRAIL XIX: Time delays in 18 strongly lensed quasars from 15 years of optical monitoring
• Accretion Disc Time Lag Distributions: Applying CREAM to Simulated AGN Light Curves
• The Transverse Peculiar Velocity of the Q2237+0305 Lens Galaxy and the Mean Mass of Its Stars
• COSMOGRAIL XVII: Time delays for the quadruply imaged quasar PG 1115+080
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XII. Time delays of the doubly lensed quasars SDSS J1206+4332 and HS 2209+1914
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XIV. Time delay of the doubly lensed quasar SDSS J1001+5027
• The Optical, Ultraviolet, and X-ray Structure of the Quasar HE 0435-1223
• TDCOSMO II: 6 new time delays in lensed quasars from high-cadence monitoring at the MPIA 2.2m telescope
• COSMOGRAIL XVIII: time delays of the quadruply lensed quasar WFI2033-4723
• On Reverberation Mapping Lag Uncertainties
• Discovery of the Lensed Quasar System DES J0408-5354
• Probing Planets in Extragalactic Galaxies Using Quasar Microlensing
• 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
• Time delay between images of the lensed quasar UM673
• Twisted quasar light curves: implications for continuum reverberation mapping of accretion disks
• Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping
• Long-term monitoring, time delay and microlensing in the gravitational lens system Q0142-100

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• Consequences of the lack of azimuthal freedom in the modeling of lensing galaxies
• Testing Super-Eddington Accretion onto a Supermassive Black Hole: Reverberation Mapping of PG 1119+120
• Joint ALMA/X-ray monitoring of the radio-quiet type 1 AGN IC 4329A
• TD-CARMA: Painless, accurate, and scalable estimates of gravitational-lens time delays with flexible CARMA processes
• Connecting the X-ray/UV variability of Fairall 9 with NICER: A Possible Warm Corona
• TDCOSMO XVII. New time delays in 22 lensed quasars from optical monitoring with the ESO-VST 2.6m and MPG 2.2m telescopes
• Scalable and Robust Multiband Modeling of AGN Light Curves in Rubin-LSST
• HALO I: Photometric continuum reverberation mapping of Fairall 9
• Accretion disc reverberation mapping of the quasar 3C 273
• Can a time evolving, asymmetric broad line region mimic a massive black hole binary?