Identification of Galaxy-Galaxy Strong Lens Candidates in the DECam Local Volume Exploration Survey Using Machine Learning

E. A. Zaborowski, A. Drlica-Wagner, F. Ashmead, J. F. Wu, R. Morgan, C. R. Bom, A. J. Shajib, S. Birrer, W. Cerny, E. J. Buckley-Geer, B. Mutlu-Pakdil, P. S. Ferguson, K. Glazebrook, S. J.Gonzalez Lozano, Y. Gordon, M. Martinez, V. Manwadkar, J. O'Donnell, J. Poh, A. RileyJ. D. Sakowska, L. Santana-Silva, B. X. Santiago, D. Sluse, C. Y. Tan, E. J. Tollerud, A. Verma, J. A. Carballo-Bello, Y. Choi, D. J. James, N. Kuropatkin, C. E. Martinez-Vazquez, D. L. Nidever, J. L.Nilo Castellon, N. E.D. Noël, K. A.G. Olsen, A. B. Pace, S. Mau, B. Yanny, A. Zenteno, T. M.C. Abbott, M. Aguena, O. Alves, F. Andrade-Oliveira, S. Bocquet, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, F. J. Castander, C. J. Conselice, M. Costanzi, M. E.S. Pereira, J. De Vicente, S. Desai, J. P. Dietrich, P. Doel, S. Everett, I. Ferrero, B. Flaugher, D. Friedel, J. Frieman, J. Garcia-Bellido, D. Gruen, R. A. Gruendl, G. Gutierrez, S. R. Hinton, D. L. Hollowood, K. Honscheid, K. Kuehn, H. Lin, J. L. Marshall, P. Melchior, J. Mena-Fernandez, F. Menanteau, R. Miquel, A. Palmese, F. Paz-Chinchon, A. Pieres, A. A.Plazas Malagon, J. Prat, M. Rodriguez-Monroy, A. K. Romer, E. Sanchez, V. Scarpine, I. Sevilla-Noarbe, M. Smith, E. Suchyta, C. To, N. Weaverdyck

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


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, which contains 1/4520 million astronomical sources covering 1/44000 deg2 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 Dark Energy Camera data, we apply color and magnitude cuts to select a catalog of 1/411 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 (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 > 10 deg) and southern celestial hemisphere (decl. < 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 that 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.

Original languageEnglish (US)
Article number68
JournalAstrophysical Journal
Issue number1
StatePublished - Sep 1 2023

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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