Lilit V. Barkhudaryan
Center for Cosmology and Astrophysics, Alikhanian National Science Laboratory, Yerevan, Armenia

Abstract
We present a spectroscopic study of Type Ia supernovae (SNe Ia), focusing on ejecta expansion velocities derived from silicon absorption lines. By separating SNe Ia into normal- and high-velocity groups, we examine their spatial distribution within host galaxies and explore links with host properties such as mass, metallicity, and stellar population age. Our analysis reveals no significant dependence between velocity groups and host galaxy characteristics, suggesting that local environments play a minor role. Instead, intrinsic factors-such as progenitor system characteristics, explosion mechanisms, and viewing geometry-appear to have a more decisive influence. Importantly, our results are based on a large SN sample that includes many events from untargeted surveys, in contrast to previous studies primarily relying on targeted surveys biased toward specific host galaxy properties. These findings offer new insights into the complex nature of SN Ia diversity and its implications for progenitor models and explosion physics.

2025 November 14, 13:30

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