NO STRIPPED HYDROGEN IN THE NEBULAR SPECTRA OF NEARBY TYPE Ia SUPERNOVA 2011fe
NO STRIPPED HYDROGEN IN THE NEBULAR SPECTRA OF NEARBY TYPE Ia SUPERNOVA 2011fe
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DOI：
10.1088/2041-8205/762/1/l5
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发表时间：
2012-10
期刊：
影响因子：
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通讯作者：
B. Shappee;K. Stanek;R. Pogge;P. Garnavich
中科院分区：
文献类型：
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作者：
B. Shappee;K. Stanek;R. Pogge;P. Garnavich
Ia型超新星的单简并模型的一般预测是，超新星喷出物将从施主恒星剥离相当数量的物质(巨型施主为∼0.5M☉，主序施主为∼0.15M☉)。这种物质受到放射性衰变产生的伽马射线的激发，一旦超新星进入星云阶段，就会产生相对较窄的(≲1,000公里S−1)发射特征。这种排放从未被检测到，这已经对Ia型前体模型提供了很强的限制。在这封信中，我们报道了用大双筒望远镜的多目标双光谱仪在B波段最大光后274天，利用附近正常的SN Ia2011Fe274天的高信噪比光谱获得的SnIa星云光谱中来自剥离的氢的Hα发射的最深极限。我们给出了Hα通量的保守上限为3.14×10−17erg S−1 cm−2，相当于光度为1.5 7×10 35erg S−1。通过文献中的定标模型，我们的通量上限转化为剥离物质的≲0.001 M☉。这比之前的限制要高出一个数量级。SN 2011Fe是一个典型的SN Ia，只是在它的附近有特殊之处，我们认为它的星云光谱中缺乏氢发射为SNE Ia的单简并模型增加了另一个强烈的限制。
A generic prediction of the single-degenerate model for Type Ia supernovae (SNe Ia) is that a significant amount of material will be stripped from the donor star (∼0.5 M☉ for a giant donor and ∼0.15 M☉ for a main-sequence donor) by the supernova ejecta. This material, excited by gamma-rays from radioactive decay, would then produce relatively narrow (≲1000 km s−1) emission features observable once the supernova enters the nebular phase. Such emission has never been detected, which already provides strong constraints on Type Ia progenitor models. In this Letter, we report the deepest limit yet on the presence of Hα emission originating from the stripped hydrogen in the nebular spectrum of an SN Ia obtained using a high signal-to-noise spectrum of the nearby normal SN Ia 2011fe 274 days after B-band maximum light with the Large Binocular Telescope's Multi-Object Double Spectrograph. We put a conservative upper limit on the Hα flux of 3.14 × 10−17 erg s−1 cm−2, which corresponds to a luminosity of 1.57 × 1035 erg s−1. By scaling models from the literature, our flux limit translates into an upper limit of ≲0.001 M☉ of stripped material. This is an order of magnitude stronger than previous limits. SN 2011fe was a typical SN Ia, special only in its proximity, and we argue that lack of hydrogen emission in its nebular spectrum adds yet another strong constraint on the single-degenerate class of models for SNe Ia.