SNe from Surveys and Patrols

Extract

The name of Zwicky is attached to the first photographic Palomar Survey and to the History of SNe study. An exciting study resumed by the striking image (M = −19) of a transient source appearing at extragalactic distance, as bright as the total magnitude of its parent galaxy. Expected to explode once a century, such an event is rare. But the more galaxies are checked the more SNe are found. That is why the wide-field is a good tool. The Palomar team SNe activity was followed by a quiet period of the whole SNe discovery (Fig. 1); from those the Cero El Robles search emerged in the early eighties. Several important patrols continued with Schmidt telescopes of size about 0.5 m (Bern, Hungary, Urss…) in spite of the low level of SNe found. Important because knowing that no SN exploded in a galaxy (especially in the sample of nearby galaxies) is the basis of the statistics. The SNe production increased in the late eighties. At the same time, the closest modern SN (1987A) led for the first time to the use of a number of instruments complementing each other to increase our understanding of SNe. But more important than the production of new SNe, is the increase of their spectroscopic classification which is necessary to the SNe work.