The Rate of Type Ia Supernovae at High Redshift

We derive the rates of Type Ia supernovae (SNIa) over a wide range ofredshifts using a complete sample from the IfA Deep Survey. This sample of morethan 100 SNIa is the largest set ever collected from a single survey, andtherefore uniquely powerful for a detailed supernova rate (SNR) calculation.Measurements of the SNR as a function of cosmological time offer a glimpse intothe relationship between the star formation rate (SFR) and Type Ia SNR, and mayprovide evidence for the progenitor pathway. We observe a progressivelyincreasing Type Ia SNR between redshifts z~0.3-0.8. The Type Ia SNRmeasurements are consistent with a short time delay (t~1 Gyr) with respect tothe SFR, indicating a fairly prompt evolution of SNIa progenitor systems. Wederive a best-fit value of SFR/SNR 580 h_70^(-2) M_solar/SNIa for theconversion factor between star formation and SNIa rates, as determined for adelay time of t~1 Gyr between the SFR and the Type Ia SNR. More completemeasurements of the Type Ia SNR at z>1 are necessary to conclusively determinethe SFR--SNR relationship and constrain SNIa evolutionary pathways.Comment: 37 pages, 9 figures, accepted for publication in Astrophysical Journal. Figures 7-9 correcte