X-ray flashes tied to low-end massive stars

The supernova SN2006aj (arrow), first observed on Feb 18, 2006, and subsequently photographed by UC Berkeley's Katzman Automatic Imaging Telescope on Mt. Hamilton, Calif. UC Berkeley astronomers and their colleagues confirmed that the supernova, 440 million light years away, was the source of a brilliant X-ray flash, probably from the explosion of a massive star at the lower limit for stars becoming black holes. In this negative image, most of the black spots are stars in our own galaxy, though some faint ones may be distant galaxies. The supernova completely swamps the other stars in its galaxy. (Credit: Weidong Li, Alex Filippenko)