The NIR Secondary Maximum and Colors of SNe Ia
| Program ID | 19086 |
|---|---|
| Science Category | Stellar Physics |
| Program Type | Analysis |
| Category | Small |
| Principal Investigator | Willem Hoogendam |
| PI Institution | University of Hawaii Institute for Astronomy |
| Co-Investigators |
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| Abstract | Type Ia supernovae are premier cosmological distance indicators, yet the systematic floor of their standardization and whether it evolves with redshift remains a critical open question for next-generation cosmology. In the near-infrared, these supernovae exhibit a secondary maximum whose morphology depends not only on the mass of synthesized Ni-56 but also on the mass of stable iron-group elements, the degree of radioactive mixing, and progenitor metallicity. This sensitivity to explosion physics beyond the single parameter that dominates optical light curves makes the near-infrared a uniquely powerful diagnostic, yet no homogeneous sample with sufficient phase coverage from rise through the secondary maximum exists. The Roman High-Latitude Time-Domain Survey will deliver this sample for the first time, providing rest-frame near-infrared observations out to z of approximately 0.3 with the cadence necessary to characterize the secondary maximum in the YJH bands fully. We propose to leverage these data in three ways. First, we will define new near-infrared color-stretch standardization parameters constructed from the timescales of extrema in the J-H color evolution, analogous to the optical s_BV parameter but exploiting the richer information content of the near-infrared. Second, we will fit a generalized luminosity-width relation using these diagnostics and evaluate the reduction in Hubble residual scatter relative to existing corrections. Third, we will compare observed parameter distributions against synthetic light curves spanning a range of explosion models to constrain which scenarios are consistent with the data and whether they evolve with redshift. |