IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021A070 PROGRAM_TITLE SpeX NIR spectroscopy of Infant Type Ia supernovae PROGRAM_INV1 Melissa Shahbandeh PROGRAM_INV2 Eric Hsiao PROGRAM_INV3 David Sand PROGRAM_INV4 Mark Phillips PROGRAM_INV5 Saurabh Jha PROGRAM_SCICAT extra-galactic PROGRAM_ABSTRACT_BEG We request six classically scheduled half nights with SpeX to obtain high S/N NIR spectra of infant Type Ia supernovae [SNe Ia] hours to days after explosion and to follow them as they evolve. This SpeX program will be an integral part of a 2-month intensive observing campaign using the same follow-up resources as CSP-II [Phillips et al. 2019, Hsiao et al. 2019]. The advent of improved wide-field transient searches and a machine learning based alert broker, along with multi-color pre-screening with the 1-m Swope telescope will ensure a high likelihood of very young SNe Ia. This program aims to obtain an unprecedented data set of early time spectra and photometry to investigate the origins and mechanisms of SNe Ia. Very early-time spectra can be used to measure the outer layers of the ejecta and to distinguish between explosion mechanisms and progenitor scenarios. For example, Chandrasekhar-mass delayed detonation and sub-Chandrasekhar-mass double detonation scenarios have very different predictions for the amount and velocity of unburned carbon remaining in the very outer layer, which is most effectively studied in the early NIR C I 1.0693 um line. PROGRAM_ABSTRACT_END