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Title: Tracing back the birth environments of Type Ia supernova progenitor stars
Speaker: Dr. Young-Lo Kim / Yonsei University
Date & Time: 2025-01-21, 4:00 PM
Location: Science Hall 638
Talk to be delivered in English
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Abstract: The environmental dependence of Type Ia supernova (SN Ia) luminosities is well-established, and efforts are being made to find its origin. Previous studies typically use the currently-observed status of the host galaxy. However, given the delay time between the birth of the progenitor star and the SN Ia explosion, the currently-observed status may differ from the birth environment of the SN Ia progenitor star. In this talk, I will present how to trace back the SN Ia progenitor star birth environment, employing the chemical evolution and accurately determined stellar population properties host galaxies. Then, I will show you how the birth environment of the SN Ia progenitor star and currently-observed status of galaxies are different. Interestingly, we find that [α/Fe]_Birth clearly splits the SN Ia sample into two groups, which show a difference in weighted-means of light-curve shape parameters: 0.81 ± 0.33 (2.5σ). Finally, an application of this work and future works are presented. Also, I will introduce briefly about the Zwicky Transient Facility, where I hold ‘builder status’.
Figure description:
Distributions of SN Ia progenitor star birth (orange) and currently observed (cyan) [Fe/H] and [α/Fe] for each of the 44 host galaxies. The 34 hosts of normal SNe Ia are indicated with solid lines around each star-shaped mark. The p-values of the two-sample Kolmogorov–Smirnov test are presented in the right panels together with cumulative distributions. The birth environments for all and normal SN Ia samples have wider ranges for [Fe/H] and [α/Fe] than the currently observed environments, respectively. The p-values in the right panels show that birth and current environments are sampled from populations with different distributions, regardless of all or normal Ia host samples.
