arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1006.4259astro-ph.HE
收藏

Ic型SN 2007 gr:来自后期光学-红外光谱的喷出物普查

The Type Ic SN 2007gr: a census of the ejecta from late-time optical-infrared spectra

P. A. Mazzali, I. Maurer, S. Valenti, R. Kotak, D. Hunter

摘要:

超新星的星云光谱(SNe)提供了一个不受阻碍的视图的内部区域的喷出物,其中大多数核合成发生。光谱覆盖了大部分,但不是所有的发射元素,因此只能提供爆炸产物的部分视图。另一方面,同时的光学-红外光谱包含所有重要元素的发射线,从C和O到中等质量元素(IME)Mg、Si、S、Ca,再到Fe和Ni。特别是Si和S在IR中看得最清楚。IR数据的可用性使得更详细地探索爆炸的结果成为可能。SN 1,2007 gr是第一个可获得此类数据的Ic型SN。用NLTE代码对光谱进行建模,揭示了内部喷出物包含速度为$\approx 4500$ \,\kms的材料的$\sim 1 \Msun$。%光谱由\Nifs提供动力,其量($0.076 \Msun$)与从早期数据导出的%一致。使用来自光变曲线峰($0.076 \Msun$)的相同质量的\Nifs \为光谱提供动力,得到一致的结果。氧是主要元素,产生$\sim 0.8 \Msun$。C/O比为$< 0.2$。$\sim 0.1 \Msun$的IME帐户。这证实SN\,2007 gr是低质量CO核心的爆炸,可能是主序星质量为$\approx 15 \Msun$的结果。\CaII和\FeII的比值对假定的结块程度敏感。特别地,对于更高程度的聚集,[ \FeII ]的光学线相对于IR线变得更强。

英文摘要:

Nebular spectra of Supernovae (SNe) offer an unimpeded view of the inner region of the ejecta, where most nucleosynthesis takes place. Optical spectra cover most, but not all of the emitting elements, and therefore offer only a partial view of the products of the explosion. Simultaneous optical-infrared spectra, on the other hand, contain emission lines of all important elements, from C and O through to the Intermediate Mass Elements (IME) Mg, Si, S, Ca, and to Fe and Ni. In particular, Si and S are best seen in the IR. The availability of IR data makes it possible to explore in greater detail the results of the explosion. SN\,2007gr is the first Type Ic SN for which such data are available. Modelling the spectra with a NLTE code reveals that the inner ejecta contain $\sim 1 \Msun$ of material within a velocity of $\approx 4500$\,\kms. %The spectrum is powered by \Nifs, in an amount ($0.076 \Msun$) consistent with that %derived from the early-time data. The same mass of \Nifs\ derived from the light curve peak ($0.076 \Msun$) was used to power the spectrum, yielding consistent results. Oxygen is the dominant element, contributing $\sim 0.8 \Msun$. The C/O ratio is $< 0.2$. IME account for $\sim 0.1 \Msun$. This confirms that SN\,2007gr was the explosion of a low-mass CO core, probably the result of a star of main-sequence mass $\approx 15 \Msun$. The ratios of the \CaII\ lines, and of those of \FeII, are sensitive to the assumed degree of clumping. In particular, the optical lines of [\FeII] become stronger, relative to the IR lines, for higher degrees of clumping.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑