Type-Ia Supernova Rates to Redshift 2.4 from CLASH: The Cluster Lensing And Supernova Survey with Hubble
Cenko, S. B.; Molino, A.; Leibundgut, B.; Filippenko, A. V.; Balestra, I.; Rosati, P.; Li, C.; Maoz, D.; Dickinson, M. E.; Nonino, M.; Coe, D.; Koekemoer, A.; Mobasher, B.; U, V.; Postman, M.; Jouvel, S.; Benítez, N.; Bradley, L.; Graur, O.; McCully, C.; Medezinski, E.; Patel, B.; Garnavich, P.; Hjorth, J.; Strolger, L. -G.; Riess, A. G.; Clubb, K. I.; Holoien, T. W. -S.; Rodney, S. A.; Jha, S. W.; Dahlen, T.; Frederiksen, T. F.; Jones, D. O.; Matheson, T.; Silverman, J. M.; Jedruszczuk, K.; Lin, K.; Mirmelstein, M.; Neustadt, J.; Ovadia, A.; Rogers, E. H.
United States, Israel, Spain, Italy, Denmark, Germany
Abstract
We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, ~13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z > 1.2. We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit on the SN Ia rate in the range 1.8 < z < 2.4. The results are consistent with the rates measured by the HST/GOODS and Subaru Deep Field SN surveys. We model these results together with previous measurements at z < 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of -1.00^{+0.06(0.09)}_{-0.06(0.10)}\ (statistical) ^{+0.12}_{-0.08}\ (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at >99% significance level.