First spectroscopic evidence of microlensing on a BAL quasar ? The case of H 1413+117.

We have obtained, under optimal seeing conditions (~ 0.6" FWHM), new data for the quadruply lensed quasar H 1413 + 117 using the bidimensional spectrograph SILFID at the C.F.H. telescope. The spectra recorded for each of the four individual images turn out to be quite similar, except for the narrow absorption line systems (probably related to the lenses) seen in images A and B and for marked differences in the spectrum of image D. When compared to the 3 other images, the spectrum of D shows smaller values for the emission lines/continuum ratio and, larger equivalent width for absorption features located in the blueshifted P Cygni profile. We discuss briefly the possible explanations of these observations in terms of micro-lensing and/or intrinsic variability of the source. Key-words: Quasars (H 1413 + 117), gravitation, observational methods, spectroscopy.