_version_ 1866912686653046784
author McArthur, Everett
Millon, Martin
Powell, Meredith
Wechsler, Risa H.
Pan, Zhiwei
Siudek, Małgorzata
Spiller, Jonas
Aguilar, Jessica Nicole
Ahlen, Steven
Anand, Abhijeet
BenZvi, Segev
Bianchi, Davide
Brooks, David
Claybaugh, Todd
Cuceu, Andrei
de la Macorra, Axel
Dey, Arjun
Doel, Peter
Font-Ribera, Andreu
Forero-Romero, Jaime E.
Gaztañaga, Enrique
Gontcho, Satya Gontcho A
Gutierrez, Gaston
Herrera-Alcantar, Hiram K.
Honscheid, Klaus
Ishak, Mustapha
Joyce, Dick
Juneau, Stephanie
Kirkby, David
Kisner, Theodore
Kremin, Anthony
Lahav, Ofer
Lamman, Claire
Landriau, Martin
Guillou, Laurent Le
Manera, Marc
Meisner, Aaron
Miquel, Ramon
Nadathur, Seshadri
Palanque-Delabrouille, Nathalie
Percival, Will
Poppett, Claire
Prada, Francisco
Pérez-Ràfols, Ignasi
Rossi, Graziano
Sanchez, Eusebio
Schlegel, David
Schubnell, Michael
Seo, Hee-Jong
Silber, Joseph Harry
Sprayberry, David
Tarlé, Gregory
Weaver, Benjamin Alan
Zhou, Rongpu
Zou, Hu
author_facet McArthur, Everett
Millon, Martin
Powell, Meredith
Wechsler, Risa H.
Pan, Zhiwei
Siudek, Małgorzata
Spiller, Jonas
Aguilar, Jessica Nicole
Ahlen, Steven
Anand, Abhijeet
BenZvi, Segev
Bianchi, Davide
Brooks, David
Claybaugh, Todd
Cuceu, Andrei
de la Macorra, Axel
Dey, Arjun
Doel, Peter
Font-Ribera, Andreu
Forero-Romero, Jaime E.
Gaztañaga, Enrique
Gontcho, Satya Gontcho A
Gutierrez, Gaston
Herrera-Alcantar, Hiram K.
Honscheid, Klaus
Ishak, Mustapha
Joyce, Dick
Juneau, Stephanie
Kirkby, David
Kisner, Theodore
Kremin, Anthony
Lahav, Ofer
Lamman, Claire
Landriau, Martin
Guillou, Laurent Le
Manera, Marc
Meisner, Aaron
Miquel, Ramon
Nadathur, Seshadri
Palanque-Delabrouille, Nathalie
Percival, Will
Poppett, Claire
Prada, Francisco
Pérez-Ràfols, Ignasi
Rossi, Graziano
Sanchez, Eusebio
Schlegel, David
Schubnell, Michael
Seo, Hee-Jong
Silber, Joseph Harry
Sprayberry, David
Tarlé, Gregory
Weaver, Benjamin Alan
Zhou, Rongpu
Zou, Hu
contents Quasars acting as strong gravitational lenses offer a rare opportunity to probe the redshift evolution of scaling relations between supermassive black holes and their host galaxies, particularly the $M_{\mathrm{BH}}$--$M_{\mathrm{host}}$ relation. Using these powerful probes, the mass of the host galaxy can be precisely inferred from the Einstein radius $θ_{\mathrm{E}}$. Using 812{,}118 quasars from DESI DR1 ($0.03 \leq z \leq 1.8$), we searched for quasars lensing higher-redshift galaxies by identifying background emission-line features in their spectra. To detect these rare systems, we trained a convolutional neural network (CNN) on mock lenses constructed from real DESI spectra of quasars and emission-line galaxies (ELGs), achieving a high classification performance (AUC = 0.99). We also trained a regression network to estimate the redshift of the background ELG. Applying this pipeline, we identified seven high-quality (Grade~A) lens candidates, each exhibiting a strong [O\,\textsc{ii}] doublet at a higher redshift than the foreground quasar; four candidates additionally show H$β$ and [O\,\textsc{iii}] emission. These results significantly expand the sample of quasar lens candidates beyond the twelve identified and three confirmed in previous work, and demonstrate the potential for scalable, data-driven discovery of quasars as strong lenses in upcoming spectroscopic surveys.
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id arxiv_https___arxiv_org_abs_2511_02009
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quasars acting as Strong Lenses Found in DESI DR1
McArthur, Everett
Millon, Martin
Powell, Meredith
Wechsler, Risa H.
Pan, Zhiwei
Siudek, Małgorzata
Spiller, Jonas
Aguilar, Jessica Nicole
Ahlen, Steven
Anand, Abhijeet
BenZvi, Segev
Bianchi, Davide
Brooks, David
Claybaugh, Todd
Cuceu, Andrei
de la Macorra, Axel
Dey, Arjun
Doel, Peter
Font-Ribera, Andreu
Forero-Romero, Jaime E.
Gaztañaga, Enrique
Gontcho, Satya Gontcho A
Gutierrez, Gaston
Herrera-Alcantar, Hiram K.
Honscheid, Klaus
Ishak, Mustapha
Joyce, Dick
Juneau, Stephanie
Kirkby, David
Kisner, Theodore
Kremin, Anthony
Lahav, Ofer
Lamman, Claire
Landriau, Martin
Guillou, Laurent Le
Manera, Marc
Meisner, Aaron
Miquel, Ramon
Nadathur, Seshadri
Palanque-Delabrouille, Nathalie
Percival, Will
Poppett, Claire
Prada, Francisco
Pérez-Ràfols, Ignasi
Rossi, Graziano
Sanchez, Eusebio
Schlegel, David
Schubnell, Michael
Seo, Hee-Jong
Silber, Joseph Harry
Sprayberry, David
Tarlé, Gregory
Weaver, Benjamin Alan
Zhou, Rongpu
Zou, Hu
Astrophysics of Galaxies
Quasars acting as strong gravitational lenses offer a rare opportunity to probe the redshift evolution of scaling relations between supermassive black holes and their host galaxies, particularly the $M_{\mathrm{BH}}$--$M_{\mathrm{host}}$ relation. Using these powerful probes, the mass of the host galaxy can be precisely inferred from the Einstein radius $θ_{\mathrm{E}}$. Using 812{,}118 quasars from DESI DR1 ($0.03 \leq z \leq 1.8$), we searched for quasars lensing higher-redshift galaxies by identifying background emission-line features in their spectra. To detect these rare systems, we trained a convolutional neural network (CNN) on mock lenses constructed from real DESI spectra of quasars and emission-line galaxies (ELGs), achieving a high classification performance (AUC = 0.99). We also trained a regression network to estimate the redshift of the background ELG. Applying this pipeline, we identified seven high-quality (Grade~A) lens candidates, each exhibiting a strong [O\,\textsc{ii}] doublet at a higher redshift than the foreground quasar; four candidates additionally show H$β$ and [O\,\textsc{iii}] emission. These results significantly expand the sample of quasar lens candidates beyond the twelve identified and three confirmed in previous work, and demonstrate the potential for scalable, data-driven discovery of quasars as strong lenses in upcoming spectroscopic surveys.
title Quasars acting as Strong Lenses Found in DESI DR1
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2511.02009