Strong lensing in UNIONS: Toward a pipeline from discovery to modeling

Abstract

We present a search for galaxy-scale strong gravitational lenses in the initial 2 500 square degrees of the Canada-France Imaging Survey (CFIS). We designed a convolutional neural network (CNN) committee that we applied to a selection of 2 344 002 exquisite-seeing $r$-band images of color-selected luminous red galaxies (LRGs). Our classification uses a realistic training set where the lensing galaxies and the lensed sources are both taken from real data, namely the CFIS $r$-band images themselves and the Hubble Space Telescope (HST). A total of 9 460 candidates obtain a score above 0.5 with the CNN committee. After a visual inspection of the candidates, we find a total of 133 lens candidates, of which 104 are completely new. The set of false positives mainly contains ring, spiral, and merger galaxies, and to a lesser extent galaxies with nearby companions. We classify 32 of the lens candidates as secure lenses and 101 as maybe lenses. For the 32 highest quality lenses, we also fit a singular isothermal ellipsoid mass profile with external shear along with an elliptical Sersic profile for the lens and source light. This automated modeling step provides distributions of properties for both sources and lenses that have Einstein radii in the range $0.5\arcsec<θ_E<2.5\arcsec$. Finally, we introduce a new lens and/or source single-band deblending algorithm based on auto-encoder representation of our candidates. This is the first time an end-to-end lens-finding and modeling pipeline is assembled together, in view of future lens searches in a single band, as will be possible with Euclid.

arXiv comment29 pages, 21 figures, accepted by A&A, in press

References in corpus (91)

• emcee: The MCMC Hammer
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• The SIMBAD astronomical database
• Overview of the DESI Legacy Imaging Surveys
• The VizieR database of Astronomical Catalogues
• H0LiCOW XIII. A 2.4% measurement of $H_0$ from lensed quasars: $5.3\sigma$ tension between early and late-Universe probes
• The COSMOS2015 Catalog: Exploring the 1<z<6 Universe with half a million galaxies
• The Hyper Suprime-Cam SSP Survey: Overview and Survey Design
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
• Spectroscopic Target Selection for the Sloan Digital Sky Survey: The Luminous Red Galaxy Sample
• Delving Deep into Rectifiers: Surpassing Human-Level Performance on ImageNet Classification
• zCOSMOS: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field
• Direct Detection of CDM Substructure
• The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies
• 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
• The Sloan Lens ACS Survey. V. The Full ACS Strong-Lens Sample
• The Cosmic Lens All-Sky Survey: I. Source selection and observations
• Gravitational detection of a low-mass dark satellite at cosmological distance
• H0LiCOW I. $H_0$ Lenses in COSMOGRAIL's Wellspring: Program Overview
• The VIMOS Ultra-Deep Survey: ~10,000 galaxies with spectroscopic redshifts to study galaxy assembly at early epochs 2<z<~6
• The population of galaxy-galaxy strong lenses in forthcoming optical imaging surveys
• The Cosmic Lens All-Sky Survey:II. Gravitational lens candidate selection and follow-up
• Galaxy And Mass Assembly (GAMA): Structural Investigation of Galaxies via Model Analysis (SIGMA)
• Extragalactic millimeter-wave sources in South Pole Telescope survey data: source counts, catalog, and statistics for an 87 square-degree field
• Detection of lensing substructure using ALMA observations of the dusty galaxy SDP.81
• The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees
• Lenstronomy: multi-purpose gravitational lens modelling software package
• Detection of a Dark Substructure through Gravitational Imaging
• Bayesian Strong Gravitational-Lens Modeling on Adaptive Grids: Objective Detection of Mass Substructure in Galaxies
• The Sloan Lens ACS Survey. IX. Colors, Lensing and Stellar Masses of Early-type Galaxies
• The universality of the virial halo mass function and models for non-universality of other halo definitions
• The Structure and Dynamics of Luminous and Dark Matter in the Early-Type Lens Galaxy of 0047-281 at z=0.485
• The DEIMOS 10k spectroscopic survey catalog of the COSMOS field
• Gravitational Lens Models Based on Submillimeter Array Imaging of Herschel-selected Strongly Lensed Sub-millimeter Galaxies at z>1.5
• MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre
• Inference of the Cold Dark Matter substructure mass function at z=0.2 using strong gravitational lenses
• The BOSS Emission-Line Lens Survey (BELLS). I. A large spectroscopically selected sample of Lens Galaxies at redshift ~ 0.5
• The Halos of Satellite Galaxies: the Companion of the Massive Elliptical Lens SL2S J08544-0121
• Finding Strong Gravitational Lenses in the Kilo Degree Survey with Convolutional Neural Networks
• The CFHTLS Strong Lensing Legacy Survey: I. Survey overview and T0002 release sample
• HerMES: Candidate Gravitationally Lensed Galaxies and Lensing Statistics at Submillimeter Wavelengths
• The Sloan Digital Sky Survey Quasar Lens Search. I. Candidate Selection Algorithm
• Disentangling Baryons and Dark Matter in the Spiral Gravitational Lens B1933+503
• Gravitational lens modeling with basis sets
• The SL2S Galaxy-scale Lens Sample. V. Dark Matter Halos and Stellar IMF of Massive Early-type Galaxies out to Redshift 0.8
• The FMOS-COSMOS survey of star-forming galaxies at z~1.6 III. Survey design, performance, and sample characteristics
• The Strong Gravitational Lens Finding Challenge
• First catalog of strong lens candidates in the COSMOS field
• The Herschel-ATLAS: a sample of 500μm-selected lensed galaxies over 600 square degrees
• Dark matter halos of massive elliptical galaxies at $z\sim 0.2$ are well described by the Navarro-Frenk-White profile
• AutoLens: Automated Modeling of a Strong Lens's Light, Mass and Source
• The VIMOS Ultra Deep Survey First Data Release: spectra and spectroscopic redshifts of 698 objects up to z~6 in CANDELS
• Low-mass halo perturbations in strong gravitational lenses at redshift z$\sim$0.5 are consistent with CDM
• Planck's Dusty GEMS: Gravitationally lensed high-redshift galaxies discovered with the Planck survey
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). I. Automatic search for galaxy-scale strong lenses
• Finding high-redshift strong lenses in DES using convolutional neural networks
• The Sloan Lens ACS Survey. XII. Extending Strong Lensing to Lower Masses
• Finding Strong Gravitational Lenses in the DESI DECam Legacy Survey
• The Canada-France Imaging Survey: First results from the u-band component
• Constraining sterile neutrino cosmologies with strong gravitational lensing observations at redshift z~0.2
• Discovering New Strong Gravitational Lenses in the DESI Legacy Imaging Surveys
• SCARLET: Source separation in multi-band images by Constrained Matrix Factorization
• Galaxy Zoo: Morphological Classifications for 120,000 Galaxies in HST Legacy Imaging
• The 0.1<z<1.65 evolution of the bright end of the [OII] luminosity function
• Candidate Gravitationally Lensed Dusty Star-forming Galaxies in the Herschel Wide Area Surveys
• The SL2S Galaxy-scale Gravitational Lens Sample. I. The alignment of mass and light in massive early-type galaxies at z=0.2-0.9
• Automated detection of galaxy-scale gravitational lenses in high resolution imaging data
• HOLISMOKES -- II. Identifying galaxy-scale strong gravitational lenses in Pan-STARRS using convolutional neural networks
• LensExtractor: A Convolutional Neural Network in Search of Strong Gravitational Lenses
• The Canada-France Imaging Survey: Reconstructing the Milky Way Star Formation History from its White Dwarf Population
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). II. Environments and Line-of-Sight Structure of Strong Gravitational Lens Galaxies to z ~ 0.8
• Survey of gravitationally-lensed objects in HSC imaging (SuGOHI). III. Statistical strong lensing constraints on the stellar IMF of CMASS galaxies
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps
• Deep Generative Models for Galaxy Image Simulations
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). IV. Lensed quasar search in the HSC survey
• CHITAH: Strong-gravitational-lens hunter in imaging surveys
• The inner mass power spectrum of galaxies using strong gravitational lensing: beyond linear approximation
• Five New High-Redshift Quasar Lenses from the Sloan Digital Sky Survey
• HOLISMOKES -- IV. Efficient mass modeling of strong lenses through deep learning
• Strong lensing in UNIONS: Toward a pipeline from discovery to modeling
• Total density profile of massive early-type galaxies in Horizon-AGN simulation: impact of AGN feedback and comparison with observations
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: A Catalogue of Strong Galaxy-Galaxy Lens Candidates
• A seven square degrees survey for galaxy-scale gravitational lenses with the HST imaging archive
• Survey of Gravitationally lensed Objects in HSC Imaging (SuGOHI) -- VII. Discovery and Confirmation of Three Strongly Lensed Quasars
• Multi-band morpho-Spectral Component Analysis Deblending Tool (MuSCADeT): Deblending colourful objects
• ALMA view of RX J1131-1231: Sub-kpc CO (2-1) mapping of a molecular disk in a lensed star-forming quasar host galaxy
• SEAGLE--II: Constraints on feedback models in galaxy formation from massive early type strong lens galaxies
• Zooming into the Cosmic Horseshoe: new insights on the lens profile and the source shape
• Discovery of an unusually compact lensed Lyman Break Galaxy from the Hyper Suprime-Cam Survey
• Do gravitational lens galaxies have an excess of luminous substructure?

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• Euclid Preparation XXXIII. Characterization of convolutional neural networks for the identification of galaxy-galaxy strong lensing events
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