$\star$ Reduction of the supernovæ of the countryside of spring 2001

The 6 supernovæ of our batch present several measurements made since the ground, in particular, the images which made it possible to detect them, the corresponding points in the lightcurve are of primary importance because they are before the maximum of luminosity. They make it possible in particular to have an estimate much more precise parameters of the lightcurve (the factor of stretching and the day of the maximum).

As we saw at the time of the chapter of detection the observations of research are made in two times: the reference period and the period of research. These two periods are generally separated from approximately three to four weeks. In our case, the duration was 20 days, it was thus extremely probable that light of the supernova is already present on the image of reference. For the estimate of the lightcurve, it was essential to have images of reference without the supernova.

The fields chosen for marketing year 2001 were partly the same ones as for the research project 2000 campaign and 2002 carried out with the CFHT. These images were thus used like reference to build the lightcurves on the ground of supernovæ CFHT.

For the supernovæ discovered with the CTIO, the fields observed in 2001, were observed again at the time of the marketing year 2002 with the CTIO. Some complementary observations were carried out with the VLT, in particular, for the references in R of 2001gq.