DOI: 10.5281/zenodo.15320520
title: Gravitational Lenses in UNIONS and Euclid (GLUE) I: A Search for Strong Gravitational Lenses in UNIONS with Subaru, CFHT, and Pan-STARRS Data

description: This repository shares the complete catalog of candidates identified in the first GLUE search in UNIONS, along with their corresponding RGB images. These strong lens candidates were identified by use of a residual neural network (ResNet). The search process is desrcibed in detail in Storfer et al. 2025 (link).

 

Strong Lens Candidate Catalog:

The file containing the strong lens cadidates is storfer_2025_lens_candidates_UNIONS.csv

There are a total of 1346 candidates; 146 Grade A, 199 Grade B, and 1001 Grade C.

The catalog contains the folowing columns:




sys_name
name of the system (right ascension and declination in decimal format using J2000; formatted as GLUE-###.####+##.####) 


ra
right ascension of the putative lens galaxy in degrees


dec
declination of the putative lens galaxy in degrees


grade
letter grade assigned in visual inspection (grades A, B, and C included)


score
averaged numerical score from both human inspectors (C.J.S. and E.M.); (4.0, 3.5): A, (3.0): B, (2.5, 2.0): C)


mag_g
g-band magnitude from the DESI Legacy Surveys, assigned by the Tractor model (Lang+ 2016)


mag_r
r-band magnitude from the DESI Legacy Surveys, assigned by the Tractor model (Lang+ 2016)


mag_z
z-band magnitude from the DESI Legacy Surveys, assigned by the Tractor model (Lang+ 2016)


brickname
name of brick in the DESI Legacy Surveys, encoding the brick sky position (e.g. "1126p222" near RA=112.6, Dec=+22.2; Lang+ 2016)


objid
catalog object number within the DESI Legacy Surveys brick and is contiguously enumerated within each brick (Lang+ 2016)


type
the object morphological model type from the Tractor: "PSF"=stellar, "REX"="round exponential galaxy", "DEV"=deVaucouleur, "EXP"=exponential, "SER"=Sersic. See also the larger description.


model_pred1
predicted probability from Model 1 for the image of the candidate


model_pred2
predicted probability from Model 2 for the image of the candidate


photozd
mean photometric redshift for the putative lens galaxy from the DESI Legacy Surveys photometry (Zhou et al. 2020)


photzd_std
standard deviation of the photometric redshifts 


speczd_sdss
spectroscopic redshift for the putative lens galaxy from the SDSS Data Release 18 (DR18)


speczd_desi
spectroscopic redshift for the putative lens galaxy from DESI Data Release 1 (DR1)


speczs
spectroscopic redshift for the putative source galaxy where available, identified via spectral superposition by eye


reference
reference for publications which also (independently) identify these systems




 

 

 

Individual Strong Lens Candidate Cutout Images

The zip file included here (lens_candidate_cutouts.zip) contains RGB renderings as well as individual g, r, and i band images for each of the 1346 candidates reported in Storfer et al. 2025. These images are 140 x 140 pixels or approximately 24" x 24". Red, green, and blue channels correspond to the g, r, and i band images, respectively. The directory is structure such that each system has a corresponding folder, named as the system name, within which are the RGB and single band images.