ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Instrument O O O O O O O O O O O B-Survey O B-Survey O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Survey O O O O O O B-Survey O O O O O O O O O O O O O O O O O O O O O O B-Survey O O O O O O O O O B-Survey O O O O O O O B-Formula I-Formula I-Formula I-Formula O B-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O B-Wavelength O O B-Wavelength O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: we have optimistically ignored flux and noise from unsubtracted host-galaxy light that will be there as a consequence of not having a galaxy template at the time of classification. Even if a spectrum of the host galaxy does exist (e.g., from a ground-based spectrograph), the exact galaxy SED at the position of the SN will not be accurately measured. The SN Ia efficiency for a given selection cut (see Section 3.1 ) is shown in Figure 6 . Efficiency is defined as the number of SNe correctly identified as Type Ia and passing each cut, divided by the number of SNe Ia that pass Cut 0. This calculation is per 0.1 redshift bin. SNe that pass Cut 4 have short-, medium-, and deep-exposure IFC-S spectra, in addition to the six short follow-up spectra. Figure 6. SDT and SDT* (left and right panels, respectively) SN Ia selection efficiency as a function of redshift. Efficiency is defined as the number of SNe correctly identified as Type Ia within each cut, divided by the number of SNe Ia that pass Cut 0 (see Section 3.1 ). The efficiency is calculated per 0.1 redshift bin. The gold squares, green diamonds, blue triangles, and black circles represent the efficiency of SNe Ia that pass Cuts 1, 2, 3, and 4 respectively. Lines connect data from the same tier of the survey. The large drop in efficiency from the first to the second cut at z 0.8 for the SDT strategy is caused primarily by the SDT requirement that the SN flux rises between each epoch. Comparison of the two strategies suggests that the looser selection criteria of the SDT* strategy is significantly more efficient than that of the SDT. The efficiency is low at particular redshifts, 0.3 z ≤ 0.4 and 0.7 z ≤ 0.8. This efficiency gap is partially the result of the survey design producing insufficient SN discoveries at the high- z end of each tier. However, photometric selection criteria that require the color to be consistent with an SN Ia at their host-galaxy redshift, and that the flux rise between epochs, are the main contributors to the low efficiency. For the shallow imaging tier, which covers 0.1 ≤ z 0.4, these criteria are problematic due to the tier’s short 13 s exposure, which results in noisy light curves and an undetectable rise value. The large reduction in the number of SNe between Cuts 1 and 2 is also caused by the required increase in flux between epochs. In many cases, statistical noise causes a candidate to appear to fade between two successive epochs. To reduce this selection artifact, this criterion is loosened via the iterative examination of a range of measured rise values (including negative values) for the simulated SNe Ia as a function of redshift for each tier, and a looser cut is applied. The requirements on the discovery colors ( Y − J for shallow, J − H for medium and deep) are also tightened, excluding some of the most extreme SNe Ia and significantly reducing the number of CC SNe at each step. The effect of these improved selection criteria is to increase the SN