Statistical Properties of the Nebular Spectra of 103 Stripped-envelope Core-collapse Supernovae*
Jan 27, 202231 pages
Published in:
- Astrophys.J. 928 (2022) 2, 151
- Published: Apr 4, 2022
e-Print:
- 2201.11467 [astro-ph.HE]
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Abstract: (IOP)
We present an analysis of the nebular spectra of 103 stripped-envelope (SE) supernovae (SNe) collected from the literature and observed with the Subaru Telescope from 2002 to 2012, focusing on O i λλ6300, 6363. The line profile and width of O i are employed to infer the ejecta geometry and the expansion velocity of the inner core; these two measurements are then compared with the SN subtypes, and further with the O i / Ca ii ratio, which is used as an indicator of the progenitor CO core mass. Based on the best-fit results of the O i profile, the objects are classified into different morphological groups, and we conclude that the deviation from spherical symmetry is a common feature for all types of SESNe. There is a hint (at the ∼1σ level) that the distributions of the line profile fractions are different between canonical SESNe and broad-line SNe Ic. A correlation between O i width and O i / Ca ii is discerned, indicating that the oxygen-rich material tends to expand faster for objects with a more massive CO core. Such a correlation can be utilized to constrain the relation between the progenitor mass and the kinetic energy of the explosion. Further, when O i / Ca ii increases, the fraction of objects with Gaussian O i profile increases, while those with double-peaked profile decreases. This phenomenon connects ejecta geometry and the progenitor CO core mass.Note:
- 40 pages, 23 figures, 10 tables. Accepted for publication in ApJ
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