TY - JOUR
T1 - WFI J2026-4536 and WFI J2033-4723
T2 - Two new quadruple gravitational lenses
AU - Morgan, Nicholas D.
AU - Caldwell, John A.R.
AU - Schechter, Paul L.
AU - Dressler, Alan
AU - Egami, Eiichi
AU - Rix, Hans Walter
PY - 2004/5
Y1 - 2004/5
N2 - We report the discovery of two new gravitationally lensed quasars, WFI J2026-4536 and WFI J2033-4723, at respective source redshifts of z = 2.23 and z = 1.66. Both systems are quadruply imaged and have similar PG 1115-like image configurations. WFI J2026-4536 has a maximum image separation of 1.″4, a total brightness of g = 16.5, and a relatively simple lensing environment, while WFI J2033-4723 has a maximum image separation of 2.″5, an estimated total brightness of g ≈ 17.9, and a more complicated environment of at least six galaxies within 20″. The primary lensing galaxies are detected for both systems after point-spread function subtraction. Several of the broadband flux ratios in these systems show a strong (0.1-0.4 mag) trend with wavelength, suggesting either microlensing or differential extinction through the lensing galaxy. For WFI J2026-4536, the total quasar flux has dimmed by 0.1 mag in the blue but only half as much in the red over 3 months, suggestive of microlensing-induced variations. For WFI J2033-4723, resolved spectra of some of the quasar components reveal emission-line flux ratios that agree better with the macromodel predictions than either the broadband or continuum ratios, also indicative of microlensing. The predicted differential time delays for WFI J2026-4536 are short, ranging from 1 to 2 weeks for the long delay, but are longer for WFI J2033-4723, ranging from 1 to 2 months. Both systems hold promise for future monitoring campaigns aimed at microlensing or time delay studies.
AB - We report the discovery of two new gravitationally lensed quasars, WFI J2026-4536 and WFI J2033-4723, at respective source redshifts of z = 2.23 and z = 1.66. Both systems are quadruply imaged and have similar PG 1115-like image configurations. WFI J2026-4536 has a maximum image separation of 1.″4, a total brightness of g = 16.5, and a relatively simple lensing environment, while WFI J2033-4723 has a maximum image separation of 2.″5, an estimated total brightness of g ≈ 17.9, and a more complicated environment of at least six galaxies within 20″. The primary lensing galaxies are detected for both systems after point-spread function subtraction. Several of the broadband flux ratios in these systems show a strong (0.1-0.4 mag) trend with wavelength, suggesting either microlensing or differential extinction through the lensing galaxy. For WFI J2026-4536, the total quasar flux has dimmed by 0.1 mag in the blue but only half as much in the red over 3 months, suggestive of microlensing-induced variations. For WFI J2033-4723, resolved spectra of some of the quasar components reveal emission-line flux ratios that agree better with the macromodel predictions than either the broadband or continuum ratios, also indicative of microlensing. The predicted differential time delays for WFI J2026-4536 are short, ranging from 1 to 2 weeks for the long delay, but are longer for WFI J2033-4723, ranging from 1 to 2 months. Both systems hold promise for future monitoring campaigns aimed at microlensing or time delay studies.
KW - Gravitational lensing
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U2 - 10.1086/383295
DO - 10.1086/383295
M3 - Review article
AN - SCOPUS:2942631443
SN - 0004-6256
VL - 127
SP - 2617
EP - 2630
JO - Astronomical Journal
JF - Astronomical Journal
IS - 5 1781
ER -