## 6. Implications for the lensing galaxyIf the redshift of the lens were known, we
could compute the Hubble parameter from the time delay using the
fundamental equation connecting the time delay
and the parameter As is still unknown, we cannot use this
formula to get . However, simply
Recently, values for the time delay have been predicted based on the assumption that one of the two strong metal absorption line systems at or can be identified with the deflector. R98 give yrs, Courbin et al. (1998) even yrs. Since we can reliably exclude yr, our results are not compatible with significantly larger than 1; in particular, the absorbers at 1.32 and 1.66 can be ruled out. We have searched our higher resolution NTT spectra of HE 1104-1805 (cf. Lopez et al. 1998) for absorption lines within the redshift range permitted by Fig. 4. An additional demand is that the lines should be stronger in A, as this component is located closer to the deflector. Two Mg II absorption systems, at and 0.73, meet the criteria. Of these, is acceptable only for a time delay as short as yrs, and is furthermore not compatible with the colour estimate of R98. This leaves the system at as candidate; however, the lens could also be an elliptical galaxy for which Mg II absorption would be a poor indicator. The very red colours measured by R98 support such a notion. © European Southern Observatory (ESO) 1998 Online publication: October 22, 1998 |