Progenitor diagnostics for stripped core-collapse supernovae: Measured metallicities at explosion sites

M. Modjaz, L. Kewley, J. S. Bloom, A. V. Filippenko, D. Perley, J. M. Silverman

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Metallicity is expected to influence not only the lives of massive stars but also the outcome of their deaths as supernovae (SNe) and gamma-ray bursts (GRBs). However, there are surprisingly few direct measurements of the local metallicities of different flavors of core-collapse SNe (CCSNe). Here, we present the largest existing set of host-galaxy spectra with H II region emission lines at the sites of 35 stripped-envelope CCSNe. We derive local oxygen abundances in a robust manner in order to constrain the SN Ib/c progenitor population. We obtain spectra at the SN sites, include SNe from targeted and untargeted surveys, and perform the abundance determinations using three different oxygen-abundance calibrations. The sites of SNeIc (the demise of the most heavily stripped stars, having lost both H and He layers) are systematically more metal rich than those of SNeIb (arising from stars that retained their He layer) in all calibrations. A Kolmogorov-Smirnov test yields the very low probability of 1% that SN Ib and SN Ic environment abundances, which are different on average by ∼0.2 dex (in the Pettini & Pagel scale), are drawn from the same parent population. Broad-lined SNeIc (without GRBs) occur at metallicities between those of SNeIb and SNeIc. Lastly, we find that the host-galaxy central oxygen abundance is not a good indicator of the local SN metallicity; hence, large-scale SN surveys need to obtain local abundance measurements in order to quantify the impact of metallicity on stellar death.

    Original languageEnglish (US)
    Article numberL4
    JournalAstrophysical Journal Letters
    Volume731
    Issue number1 PART II
    DOIs
    StatePublished - Apr 10 2011

    Keywords

    • galaxies: abundances
    • supernovae: general

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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