Identification of Galaxy-Galaxy Strong Lens Candidates in the DECam Local Volume Exploration Survey Using Machine Learning
Creators: name: Zaborowski, E. A.
name: Drlica-Wagner, A.
name: Ashmead, F.
name: Wu, J. F.
name: Morgan, R.
name: Bom, C. R.
name: Shajib, A. J.
name: Birrer, S.
name: Cerny, W.
name: Buckley-Geer, L.
name: Mutlu-Pakdil, B.
name: Ferguson, P. S.
name: Glazebrook, K.
name: Lozano, S. J. Gonzalez
name: Gordon, Y.
name: Martinez, M.
name: Manwadkar, V.
name: O'Donnell, J.
name: Poh, J.
name: Riley, A.
name: Sakowska, J. D.
name: Santana-Silva, L.
name: Santiago, B. X.
name: Sluse, D.
name: Tan, C. Y.
name: Tollerud, E. J.
name: Verma, A.
name: Carballo-Bello, J. A.
name: Choi, Y.
name: James, D. J.
name: Kuropatkin, N.
name: Martínez-Vázquez, C. E.
name: Nidever, D. L.
name: Castellon, J. L. Nilo
name: Noël, N. E. D.
name: Olsen, K. A. G.
name: Pace, A. B.
name: Mau, S.
name: Yanny, B.
name: Zenteno, A.
name: Abbott, T. M. C.
name: Aguena, M.
name: Alves, O.
name: Andrade-Oliveira, F.
name: Bocquet, S.
name: Brooks, D.
name: Burke, D. L.
name: Rosell, A. Carnero
name: Kind, M. Carrasco
name: Carretero, J.
name: Castander, F. J.
name: Conselice, C. J.
name: Costanzi, M.
name: Pereira, M. E. S.
name: De Vicente, J.
name: Desai, S.
name: Dietrich, J. P.
name: Doel, P.
name: Everett, S.
name: Ferrero, I.
name: Flaugher, B.
name: Friedel, D.
name: Frieman, J.
name: García-Bellido, J.
name: Gruen, D.
name: Gruendl, R. A.
name: Gutierrez, G.
name: Hinton, S. R.
name: Hollowood, D. L.
name: Honscheid, K.
name: Kuehn, K.
name: Lin, H.
name: Marshall, J. L.
name: Melchior, P.
name: Mena-Fernández, J.
name: Menanteau, F.
name: Miquel, R.
name: Palmese, A.
name: Paz-Chinchón, F.
name: Pieres, A.
name: Malagón, A. A. Plazas
name: Prat, J.
name: Rodriguez-Monroy, M.
name: Romer, A. K.
name: Sanchez, E.
name: Scarpine, V.
name: Sevilla-Noarbe, I.
name: Smith, M.
name: Suchyta, E.
name: To, C.
name: Weaverdyck, N.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We perform a search for galaxy-galaxy strong lens systems using a convolutional neural network (CNN) applied to imaging data from the first public data release of the DECam Local Volume Exploration Survey (DELVE), which contains $\sim 520$ million astronomical sources covering $\sim 4,000$ $\mathrm{deg}^2$ of the southern sky to a $5σ$ point-source depth of $g=24.3$, $r=23.9$, $i=23.3$, and $z=22.8$ mag. Following the methodology of similar searches using DECam data, we apply color and magnitude cuts to select a catalog of $\sim 11$ million extended astronomical sources. After scoring with our CNN, the highest scoring 50,000 images were visually inspected and assigned a score on a scale from 0 (definitely not a lens) to 3 (very probable lens). We present a list of 581 strong lens candidates, 562 of which are previously unreported. We categorize our candidates using their human-assigned scores, resulting in 55 Grade A candidates, 149 Grade B candidates, and 377 Grade C candidates. We additionally highlight eight potential quadruply lensed quasars from this sample. Due to the location of our search footprint in the northern Galactic cap ($b &gt; 10$ deg) and southern celestial hemisphere (${\rm Dec.}&lt;0$ deg), our candidate list has little overlap with other existing ground-based searches. Where our search footprint does overlap with other searches, we find a significant number of high-quality candidates which were previously unidentified, indicating a degree of orthogonality in our methodology. We report properties of our candidates including apparent magnitude and Einstein radius estimated from the image separation.
description: 24 pages; published version (ApJ)