We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-colour light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands, as part of the CFHT Legacy Survey (CFHTLS). Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z=1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multi-band photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: Omega M= 0.263 ±0.042;(stat) ±0.032;(sys)
Astronomers recently discovered a Type-1a supernova called SNLS-03D3bb that shines more than twice as brightly as its counterparts, researchers report in the Sept. 20 issue of the journal Nature. This along with the low kinetic energy of the star — the energy of the flying objects from the explosion — implies that the supernova originated from a white dwarf more massive than the Chandrasekhar limit.
A supernova more than twice as bright as others of its type has been observed, suggesting it arose from a star that managed to grow more massive than theoretically predicted. The observation suggests supernovae of this type are not "standard candles" as previously thought, which could affect their use as probes of dark energy – the mysterious force causing the expansion of the universe to accelerate.