Over the last few years, the Berkeley Automated Supernova Search has discovered 19 supernova. We present here preliminary measurements of supernova rates from a subset of these supernovae, which were found from a sample of well-monitored galaxies. Two effects are apparent: a surprising number of the supernovae are Type Ic supernovae, and most (17 out of 19) of the supernovae are in late spiral galaxies. Less luminous supernovae may still be escaping our attention. If the Milky Way galaxy is a late spiral, the core-collapse supernova rate (i.e., for supernovae of types II, Ib, and Ic) should be at least one supernova every 44 {plus minus} 9 years (assuming H = 75 km/sec/Mpc). A crude estimate of the core collapse supernova rate in Sc and Sbc galaxies within 5 Mpc would be one supernova every 7 years. These rates have important implications for the design of supernova neutrino, gamma-ray, and gravity-wave detectors. Plans have been developed to extend our search to a better site with more sensitivity to understand the true core-collapse supernova rate in nearby galaxies. 13 refs.
Two effects are apparent: a surprising number of the supernovae are Type Ic supernovae, and most (17 out of 19) of the supernovae are in late spiral galaxies. Less luminous supernovae may still be escaping our attention.
Can anything save you at the end of the universe? This upcoming major motion picture from United Artists, features James Spader, Angela Bassett, & Lou Diamond Phillips.
Can anything save you at the end of the universe? This upcoming major motion picture from United Artists, features James Spader, Angela Bassett, & Lou Diamond Phillips.
When you're reaching for the stars, nothing can hold you back. Star Calloway is fourteen years old, and she's the most famous pop star in the world. Her album has topped the charts, her video is all the rage, and she's about to start her world tour. There's only one thing that keeps her life from being perfect: Star's parents and baby brother have been missing for two years, and no one knows what happened to them. Still, Star knows her family would want her to be happy, and performing means everything to her. But with so many mysterious things going wrong in preparation for the tour, could the show be over before it begins?
"We describe a general formalism for computing scattering rates of weak probes in macroscopic systems, based on a density matrix formalism. We show that weak probes in general scatter off fluctuations in the medium. In the limit that the neutrino wavelength is much larger than the lengthscale of the fluctuations, we show that the scattering rate can be calculated from knowledge of the equation of state of the medium through which the neutrinos travel. Using radial profiles of a post-bounce, shocked supernova core and a well-established equation of state for nuclear matter we compute these scattering rates for various times in the vicinity of the shock. We find that, behind the shock, these correlative effects can enhance neutrino scattering rates by factors of 8 compared to standard calculations which ignore interactions in the nuclear medium. These results may have implications for how efficiently neutrinos can restart a stalled shock, although firm conclusions regarding the ultimate effects of such an enhancement await full hydrodynamic simulations, which are not performed here." --
"We describe a general formalism for computing scattering rates of weak probes in macroscopic systems, based on a density matrix formalism. We show that weak probes in general scatter off fluctuations in the medium.
A program is described for development of an automated supernova search based upon complete remote computer control of a telescope and vidicon digital imaging system. (GHT).
A program is described for development of an automated supernova search based upon complete remote computer control of a telescope and vidicon digital imaging system. (GHT).
