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We present the cosmological analysis of 752 photometrically–classified Type Ia Supernovae (SNe Ia) from the full Sloan Digital Sky Survey II (SDSS-II) Supernova (SN) Survey, supplemented host–galaxy spectroscopy from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). photometric–classificationmethod is based on the SN typing technique of Sako et al. (2011), aided host galaxy redshifts (0. 05 < z < 0. 55). SNANA simulations of our methodology estimate that have a SN Ia typing efficiency of 70. 8%, with only 3. 9% contamination from core-collapse (non-Ia). We demonstrate that this level of contamination has no effect on our cosmological constraints. quantify and correct for our selection effects (e. g. , Malmquist bias) using simulations. When fitting a flat CDM cosmological model, we find that our photometric sample alone gives Ωm = 0. 24+0. 07/−0. 05 (statistical errors only). If we relax the constraint on flatness, then our sample provides competitive statistical constraints on Ωm and Ω∆, comparable to those derived from the spectroscopically- three-year Supernova Legacy Survey (SNLS3). Using only our data, the statistics–only favors an accelerating universe at 99. 96% confidence. Assuming a constant wCDM cosmological, and combining with H0, CMB and LRG data, we obtain w = −0. 96+0. 10/−0. 10, Ωm = 0. 29+0. 02/−0. 02 and Ωk = 0. 00+0. 03/−0. 02 (statistical errors only), which is competitive with similar spectroscopically confirmed Ia analyses. Overall this comparison is reassuring, considering the lower redshift leverage of the -II SN sample (z < 0. 55) and the lack of spectroscopic confirmation used herein. These results the potential of photometrically–classified SNe Ia samples in improving cosmological.
Campbell et al. (Mon,) studied this question.