Identifying lensed quasars and measuring their time-delays from unresolved light curves

Abstract

Identifying multiply imaged quasars is challenging due to their low density in the sky and the limited angular resolution of wide field surveys. We show that multiply imaged quasars can be identified using unresolved light curves, without assuming a light curve template or any prior information. After describing our method, we show using simulations that it can attain high precision and recall when we consider high-quality data with negligible noise well below the variability of the light curves. As the noise level increases to that of the Zwicky Transient Facility (ZTF) telescope, we find that precision can remain close to $100\%$ while recall drops to $\sim 60\%$. We also consider some examples from the Time Delay Challenge 1 (TDC1) and demonstrate that the time delays can be accurately recovered from the joint light curve data in realistic observational scenarios. We further demonstrate our method by applying it to publicly available COSMOGRAIL data of the observed lensed quasar SDSS J1226-0006. We identify the system as a lensed quasar based on the unresolved light curve and estimate a time delay in good agreement with the one measured by COSMOGRAIL using the individual image light curves. The technique shows great potential to identify lensed quasars in wide field imaging surveys, especially the soon to be commissioned Vera Rubin Observatory.

arXiv commentMatches the published version, 27 pages, 23 figures

References in corpus (51)

• The Zwicky Transient Facility: System Overview, Performance, and First Results
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Tensions between the Early and the Late Universe
• H0LiCOW XIII. A 2.4% measurement of $H_0$ from lensed quasars: $5.3\sigma$ tension between early and late-Universe probes
• LSST Science Book, Version 2.0
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• The Pan-STARRS1 Surveys
• Direct Detection of CDM Substructure
• Evidence for substructure in lens galaxies?
• H0LiCOW V. New COSMOGRAIL time delays of HE0435-1223: $H_0$ to 3.8% precision from strong lensing in a flat $\Lambda$CDM model
• Strong Lensing by Galaxies
• Gravitationally lensed quasars and supernovae in future wide-field optical imaging surveys
• Compound gravitational lensing as a probe of dark matter substructure within galaxy halos
• TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles
• The Cosmic Lens All-Sky Survey:II. Gravitational lens candidate selection and follow-up
• Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens
• iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernova
• Time Delay Cosmography
• Smoothing Supernova Data to Reconstruct the Expansion History of the Universe and its Age
• Deconvolution with correct sampling
• Gravitational Lens Time Delays: A Statistical Assessment of Lens Model Dependences and Implications for the Global Hubble Constant
• Strong gravitational lensing of explosive transients
• Precision cosmology from future lensed gravitational wave and electromagnetic signals
• Strong Lens Time Delay Challenge: II. Results of TDC1
• Model independent tests of the standard cosmological model
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XI. Techniques for time delay measurement in presence of microlensing
• The stellar and dark matter distributions in elliptical galaxies from the ensemble of strong gravitational lenses
• Strongly lensed repeating Fast Radio Bursts as precision probes of the universe
• Model Independent Reconstruction of the Expansion History of the Universe and the Properties of Dark Energy
• COSMOGRAIL XIX: Time delays in 18 strongly lensed quasars from 15 years of optical monitoring
• The Hubble time inferred from 10 time-delay lenses
• TDCOSMO V: strategies for precise and accurate measurements of the Hubble constant with strong lensing
• Binary quasars
• The Dark-Matter Fraction in the Elliptical Galaxy Lensing the Quasar PG1115+080
• HOLISMOKES -- I. Highly Optimised Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals
• The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign. I. Overview and classification of candidates selected by two techniques
• Strong Lens Time Delay Challenge: I. Experimental Design
• The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2017/2018 follow-up campaign: Discovery of 10 lensed quasars and 10 quasar pairs
• Robust Strong Lensing Time Delay Estimation
• Discovering Gravitational Lenses Through Measurements Of Their Time Delays
• The lightcurve reconstruction method for measuring the time delay of gravitational lens systems
• The Quasar Pair Q 1634+267 A, B and the Binary QSO vs. Dark Lens Hypotheses
• The Initial Mass Function of Lens Galaxies from Quasar Microlensing
• Be It Unresolved: Measuring Time Delays from Lensed Supernovae
• Fast and Reliable Time Delay Estimation of Strong Lens Systems Using Method of Smoothing and Cross-Correlation
• Discovering Strongly-lensed QSOs From Unresolved Light Curves
• Measuring time delays: II. Using observations of the unresolved flux and astrometry
• Measuring time delays: I. Using a flux time series that is a linear combination of time-shifted light curves
• Out of One, Many: Distinguishing Time Delays from Lensed Supernovae
• Estimation of time delays from unresolved photometry
• Time delay estimation in unresolved lensed quasars

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• Strong lensing time-delay cosmography in the 2020s
• HOLISMOKES. VIII. High-redshift, strong-lens search in the Hyper Suprime-Cam Subaru Strategic Program
• Revising the Hubble constant, spatial curvature and dark energy dynamics with the latest observations of quasars
• Revisiting the Hubble constant, spatial curvature and cosmography with time-delay and cosmic chronometer observations
• TD-CARMA: Painless, accurate, and scalable estimates of gravitational-lens time delays with flexible CARMA processes
• Strong lensing of tidal disruption events: Detection rates in imaging surveys
• Detecting unresolved lensed SNe Ia in LSST using blended light curves
• Deep Learning Unresolved Lensed Lightcurves
• Revisiting the Hubble constant, sound horizon and cosmography from late-time Universe observations
• Time delay estimation in unresolved lensed quasars
• Harnessing Unresolved Lensed Quasars: The Mathematical Foundation of the Fluctuation Curve