The Distant Type Ia Supernova Rate

Abstract

LPNHE, CNRS-IN2P3 and Universites Paris VI & VII, Paris, France Now at IST, Lisbon, Portugal Department of Physics, Durham University, United Kingdom Institute of Astronomy, Cambridge University, United Kingdom California Institute of Technology, Pasadena, California E. O. Lawrence Berkeley National Laboratory, Berkeley, California Space Telescope Science Institute, Baltimore, Maryland Center for Particle Astrophysics, U.C. Berkeley, Berkeley, California Physics Department, University of Stockholm, Sweden Institute for Astronomy, Royal Observatory, Edinburgh, United Kingdom 11 Now at MIT, Center for space research, Cambridge, Massachusetts European Southern Observatory, La Silla, Chile 13 Space Sciences Laboratory, U.C. Berkeley, Berkeley, California Department of Astronomy, University of Barcelona, Barcelona, Spain Department of Astronomy, Yale University, New Haven, Connecticut 16 Current address: University of Texas, Austin, Texas { 2 { We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this ducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0:25-0:85. In a spatially-at cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean redshift z ' 0:55 of 1:53 0:25 +0:32 0:31 10 or 0:58 0:09 +0:10 SNu (1 SNu = 1 supernova per century per 10 LB ), where the rst uncertainty is statistical and the second includes systematic eects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit como...