Details

Autor(en) / Beteiligte

• Ostrovski, Fernanda
• McMahon, Richard G
• Connolly, Andrew J
• Lemon, Cameron A
• Auger, Matthew W
• Banerji, Manda
• Hung, Johnathan M
• Koposov, Sergey E
• Lidman, Christopher E
• Reed, Sophie L
• Allam, Sahar
• Benoit-Levy, Aurelien
• Bertin, Emmanuel
• Brooks, David
• Buckley-Geer, Elizabeth
• Rosell, Aurelio Carnero
• Kind, Matias Carrasco
• Carretero, Jorge
• Cunha, Carlos E
• da Costa, Luiz N
• Desai, Shantanu
• Diehl, H Thomas
• Dietrich, Jorg P
• Evrard, August E
• Finley, David A
• Flaugher, Brenna
• Fosalba, Pablo
• Frieman, Josh
• Gerdes, David W
• Goldstein, Daniel A
• Gruen, Daniel
• Gruendl, Robert A
• Gutierrez, Gaston
• Honscheid, Klaus
• James, David J
• Kuehn, Kyler
• Kuropatkin, Nikolay
• Lima, Marcos
• Lin, Huan
• Maia, Marcio A G
• Marshall, Jennifer L
• Martini, Paul
• Melchior, Peter
• Miquel, Ramon
• Ogando, Ricardo
• Malagon, Andres Plazas
• Reil, Kevin
• Romer, Kathy
• Sanchez, Eusebio
• Santiago, Basilio
• et. al

Titel

VDES J2325−5229 a z = 2.7 gravitationally lensed quasar discovered using morphology-independent supervised machine learning

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2017-03, Vol.465 (4), p.4325-4325

Ort / Verlag

London: Oxford University Press

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift z sub( s) = 2.74 and image separation of 2.9 arcsec lensed by a foreground z sub( l) = 0.40 elliptical galaxy. Since optical observations of gravitationally lensed quasars show the lens system as a superposition of multiple point sources and a foreground lensing galaxy, we have developed a morphology-independent multi-wavelength approach to the photometric selection of lensed quasar candidates based on Gaussian Mixture Models (GMM) supervised machine learning. Using this technique and gi multicolour photometric observations from the Dark Energy Survey (DES), near-IR JK photometry from the VISTA Hemisphere Survey (VHS) and WISE mid-IR photometry, we have identified a candidate system with two catalogue components with i sub( AB) = 18.61 and i sub( AB) = 20.44 comprising an elliptical galaxy and two blue point sources. Spectroscopic follow-up with NTT and the use of an archival AAT spectrum show that the point sources can be identified as a lensed quasar with an emission line redshift of z = 2.739 plus or minus 0.003 and a foreground early-type galaxy with z = 0.400 plus or minus 0.002. We model the system as a single isothermal ellipsoid and find the Einstein radius [thetas] sub( E) ~ 1.47 arcsec, enclosed mass M sub( enc) ~ 4 x 10 super( 11) M... and a time delay of ~52 d. The relatively wide separation, month scale time delay duration and high redshift make this an ideal system for constraining the expansion rate beyond a redshift of 1. (ProQuest: ... denotes formulae/symbols omitted.)