Characteristic velocities of stripped-envelope core-collapse supernova cores

J. I. Maurer, P. A. Mazzali, J. Deng, A. V. Filippenko, M. Hamuy, R. P. Kirshner, T. Matheson, M. Modjaz, E. Pian, M. Stritzinger, S. Taubenberger, S. Valenti

    Research output: Contribution to journalArticle

    Abstract

    The velocity of the inner ejecta of stripped-envelope core-collapse supernovae (CC-SNe) is studied by means of an analysis of their nebular spectra. Stripped-envelope CC-SNe are the result of the explosion of bare cores of massive stars (≥8 M), and their late-time spectra are typically dominated by a strong [O i]λλ6300, 6363 emission line produced by the innermost, slow-moving ejecta which are not visible at earlier times as they are located below the photosphere. A characteristic velocity of the inner ejecta is obtained for a sample of 56 stripped-envelope CC-SNe of different spectral types (IIb, Ib, Ic) using direct measurements of the linewidth as well as spectral fitting. For most SNe, this value shows a small scatter around 4500 km s-1. Observations (<100 d) of stripped-envelope CC-SNe have revealed a subclass of very energetic SNe, termed broad-lined SNe (BL-SNe) or hypernovae, which are characterized by broad absorption lines in the early-time spectra, indicative of outer ejecta moving at very high velocity (v≥ 0.1c). SNe identified as BL in the early phase show large variations of core velocities at late phases, with some having much higher and some having similar velocities with respect to regular CC-SNe. This might indicate asphericity of the inner ejecta of BL-SNe, a possibility we investigate using synthetic three-dimensional nebular spectra.

    Original languageEnglish (US)
    Pages (from-to)161-172
    Number of pages12
    JournalMonthly Notices of the Royal Astronomical Society
    Volume402
    Issue number1
    DOIs
    StatePublished - Feb 2010

    Keywords

    • Line: profiles
    • Radiative transfer
    • Supernovae: general

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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    Maurer, J. I., Mazzali, P. A., Deng, J., Filippenko, A. V., Hamuy, M., Kirshner, R. P., Matheson, T., Modjaz, M., Pian, E., Stritzinger, M., Taubenberger, S., & Valenti, S. (2010). Characteristic velocities of stripped-envelope core-collapse supernova cores. Monthly Notices of the Royal Astronomical Society, 402(1), 161-172. https://doi.org/10.1111/j.1365-2966.2009.15905.x