Hubble breaks record for furthest supernova

Record-breaking supernova in the CANDELS Ultra Deep Survey The NASA/ESA Hubble Space Telescope has broken the record in the quest to find the furthest supernova of the type used to measure cosmic distances. This supernova exploded more than 10 billion years ago (redshift 1.914), at a time the Universe was in its early formative years and stars were being born at a rapid rate. The supernova, designated SN UDS10Wil [1], belongs to a special class of exploding stars known as Type Ia supernovae. These bright beacons are prized by astronomers because they can be used as a yardstick for measuring cosmic distances, thereby yielding clues to the nature of dark Record-breaking supernova in the CANDELS Ultra Deep Survey (compass and scale) energy, the mysterious force accelerating the rate of expansion of the Universe. “This new distance record holder opens a window into the early Universe, offering important new insights into how these supernovae form,” said astronomer David O. Jones of The Johns Hopkins University in Baltimore, Md., lead author on the science paper detailing the discovery. “At that epoch, we can test theories about how reliable these detonations are for understanding the evolution of the Universe and its expansion.” One of the debates surrounding Type Ia supernovae is the nature of the fuse that ignites them....

Read More........→April 07, 2013

Celestial Fireworks When Milky Way's Giant Black Hole Swallowed A Satellite Galaxy

Julie Turner, Vanderbilt University These days the core of the Milky Way galaxy is a pretty tame place...cosmically speaking. The galactic black hole at the center is a sleeping giant. Existing stars are peacefully circling. Although conditions are favorable, there doesn’t even seem to be much new star formation going on. But there is growing evidence that several million years ago the galactic center was the site of all manner of celestial fireworks. A pair of assistant professors – Kelly Holley-Bockelmann at Vanderbilt and Tamara Bogdanović at Georgia Institute of Technology – have come up with an explanation that fits these “forensic” clues. Artist's illustration of a satellite galaxy on a collision course with the galactic black hole. Writing in the March 6 issue of the Monthly Notices of the Royal Astronomical Society, the astronomers describe how a single event – a violent collision and merger between the galactic black hole and an intermediate-sized black hole in one of the small “satellite galaxies” that circle the Milky Way – could have produced the features that point to a more violent past for the galactic core. “Tamara and I had just attended an astronomy conference in Aspen, Colorado, where several of these new observations were announced,” said Holley-Bockelmann. “It was January 2010 and a snow storm had closed...

Read More........→March 05, 2013