SN 2016coi (ASASSN-16fp): An Energetic H-stripped Core-collapse Supernova from a Massive Stellar Progenitor with Large Mass Loss
SN 2016coi (ASASSN-16fp): An Energetic H-stripped Core-collapse Supernova from a Massive Stellar Progenitor with Large Mass Loss
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DOI：
10.3847/1538-4357/ab3e37
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发表时间：
2019-05
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通讯作者：
G. Terreran;R. Margutti;D. Bersier;J. Brimacombe;D. Caprioli;P. Challis;R. Chornock;D. Coppejans;S. Dong;C. Guidorzi;K. Hurley;R. Kirshner;G. Migliori;D. Milisavljevic;David M. Palmer;J. L. Prieto;J. L. Prieto;L. Tomasella;Pablo Marchant;A. Pastorello;B. Shappee;K. Z. Stanek;M. Stritzinger;S. Benetti;Ping Chen;L. DeMarchi;N. Elias-Rosa;Christa Gall;J. Harmanen;Seppo Mattila
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作者：
G. Terreran;R. Margutti;D. Bersier;J. Brimacombe;D. Caprioli;P. Challis;R. Chornock;D. Coppejans;S. Dong;C. Guidorzi;K. Hurley;R. Kirshner;G. Migliori;D. Milisavljevic;David M. Palmer;J. L. Prieto;J. L. Prieto;L. Tomasella;Pablo Marchant;A. Pastorello;B. Shappee;K. Z. Stanek;M. Stritzinger;S. Benetti;Ping Chen;L. DeMarchi;N. Elias-Rosa;Christa Gall;J. Harmanen;Seppo Mattila
我们对高能氢剥离的SN 2016 coi（也称为SN 2016 coi）进行了全面的观测和分析。ASASSN-16 fp），通过光学和无线电波长跨越γ射线，在爆炸后的第一个小时到2420天内获得。我们的观测活动证实了他在超新星（SN）喷出物，我们解释是由一个更大的混合镍到外部喷出物层的识别。通过模拟宽的辐射热光变曲线，我们得到了一个大的喷射物质量与动能的比值（Mej = 4-7 M，Ek =（7-8）× 1051 erg）。在我们的后期光谱中观察到的小的[Ca ii] λλ 7291，7324与[O i] λλ 6300，6364的比值（<0.2）暗示了在坍缩时有一个大的祖核质量。我们发现SN 2016 coi是一个X射线（在爆炸后的前100天LX > 1039 erg s−1）和射电辐射（L8.5 GHz × 1027 erg s−1 Hz−1）的发光源。这些值与相对论SNe的值一致（2009 bb，2012 ap）。然而，对于SN 2016 coi，我们推断爆炸前的原始质量损失率为100（1-2）×，亚相对论激波速度vsh为10.15 c，这与相对论SNe形成鲜明对比，与正常SNe相似。最后，我们没有发现能量Eγ > 2 × 1046 erg的SN相关冲击爆发γ射线脉冲的证据。虽然我们不能排除双星系统中存在伴星的可能性，但我们的发现与一个巨大的单星祖先一致，该祖先在核心坍缩前经历了大量的质量损失，但在爆炸前无法完全剥离其外层。
We present comprehensive observations and analysis of the energetic H-stripped SN 2016coi (a.k.a. ASASSN-16fp), spanning the γ-ray through optical and radio wavelengths, acquired within the first hours to ∼420 days post explosion. Our observational campaign confirms the identification of He in the supernova (SN) ejecta, which we interpret to be caused by a larger mixing of Ni into the outer ejecta layers. By modeling the broad bolometric light curve, we derive a large ejecta-mass-to-kinetic-energy ratio (Mej ∼ 4–7 M⊙, Ek ∼ (7–8) × 1051 erg). The small [Ca ii] λλ7291,7324 to [O i] λλ6300,6364 ratio (∼0.2) observed in our late-time optical spectra is suggestive of a large progenitor core mass at the time of collapse. We find that SN 2016coi is a luminous source of X-rays (LX > 1039 erg s−1 in the first ∼100 days post explosion) and radio emission (L8.5 GHz ∼ 7 × 1027 erg s−1 Hz−1 at peak). These values are in line with those of relativistic SNe (2009bb, 2012ap). However, for SN 2016coi, we infer substantial pre-explosion progenitor mass loss with a rate ∼ (1–2) × and a sub-relativistic shock velocity vsh ∼ 0.15c, which is in stark contrast with relativistic SNe and similar to normal SNe. Finally, we find no evidence for a SN-associated shock breakout γ-ray pulse with energy Eγ > 2 × 1046 erg. While we cannot exclude the presence of a companion in a binary system, taken together, our findings are consistent with a massive single-star progenitor that experienced large mass loss in the years leading up to core collapse, but was unable to achieve complete stripping of its outer layers before explosion.