# # Program information file # PROGRAM_ID 2021A101 PROGRAM_TITLE Improving SN Ia IR K-Corrections for Dark Energy, Peculiar Velocities, and the Hubble Constant PROGRAM_INV1 David Rubin PROGRAM_INV2 PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT extra-galactic PROGRAM_ABSTRACT_BEG Type Ia supernovae [SNe Ia] are intrinsically superior standard candles in the rest-frame NIR. NIR observations are thus key to many large photometric SN cosmology programs, including RAISIN on Hubble, DEHVILS with UKIRT, and the future Nance Grace Roman SN survey. However, spectroscopic followup has not kept pace with these large photometric surveys. Thus, K-corrections remain uncertain due to both the limited number of spectra available [as only ~ 25 SNe have six spectra or more over their entire phase range] and the calibration uncertainties of the available spectra [many of which do not have simultaneous NIR imaging for calibration]. We thus propose to build out this sample, paying particular importance to calibration. For this semester, we propose following three SNe with a series of six spectra [one every three days] with IRTF SpeX. To obtain enough S/N for the derived K-corrections for each spectrum to be below 0.01 magnitudes, we require S/N of ~ 25 per prism resolution element. For a typical redshift of 0.02, SNe Ia in this phase range will be 16--17 magnitude in J, so this S/N is achievable with SpeX in less than an hour under typical conditions. PROGRAM_ABSTRACT_END