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Astron. Astrophys. 330, 57-62 (1998) 1. IntroductionIt is well established that gravitationally lensed quasars are
unique natural rulers for measuring the Universe and for deriving the
cosmological parameters (Refsdal, 1964a,b). Measuring the time delay
from the images of a lensed QSO can provide an estimate of the Hubble
parameter Imaging in the near IR (1 to 2.5 microns) has the advantage that the relative brightness between the lensed QSO and any lensing galaxy decreases, making the galaxy easier to detect. The disadvantage is that the IR sky is considerably brighter. This forces one to take many images to avoid detector saturation; however, this turns out to be an advantage (see Section 3). This paper presents IR observations of the quasar
HE 1104-1805. The strong similarity between the optical spectra
obtained for its two components (Wisotzki et al, 1993) makes
HE 1104-1805 a good gravitational lens candidate. The high
redshift of the object ( We used a recently developed image deconvolution algorithm (Magain, Courbin & Sohy, 1997; hereafter MCS) to optimally combine the numerous IR frames and obtain deep, sharp images of HE 1104-1805. The present paper describes how this powerful technique allows us to study the immediate environment of HE 1104-1805 and detect the lensing galaxy. ![]() ![]() ![]() ![]() © European Southern Observatory (ESO) 1998 Online publication: January 8, 1998 ![]() |