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arXiv 0904.3737astro-ph.SRastro-ph.CO
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尘埃和II型高原超新星2004 et

Dust and the type II-plateau supernova 2004et

Rubina Kotak, Peter Meikle, Duncan Farrah, Christopher Gerardy, Ryan Foley, Schuyler van Dyk, Claes Fransson, Peter Lundqvist, Jesper Sollerman, Robert Fesen, A… 展开作者

Rubina Kotak, Peter Meikle, Duncan Farrah, Christopher Gerardy, Ryan Foley, Schuyler van Dyk, Claes Fransson, Peter Lundqvist, Jesper Sollerman, Robert Fesen, Alex Filippenko, Seppo Mattila, Jeffrey Silverman, Anja Andersen, Peter Hoeflich, Monica Pozzo, J. Craig Wheeler

摘要:

我们目前的中红外(MIR)的II型高原超新星(SN)2004 et,获得与{ \it斯皮策太空望远镜}之间的64天和1406过去的爆炸。最后给出了它们的光学光谱。对于过去300-795天的爆炸,我们认为SN 2004 et的光谱能量分布包括(a)由于光学厚气体的发射以及自由束缚辐射的热分量,(b)由于喷出物中新形成的放射性加热尘埃的温暖分量,以及(c)由于宿主星系星际介质尘埃的红外回波的冷分量。NGC 6946由于喷出物中电离气体的自由-自由发射,也可能对IR SED有很小的贡献。我们揭示了有史以来第一次光谱证据硅酸盐尘埃形成的喷出物的超新星。这是支持我们检测到一个大的,但逐渐下降,质量的SiO。然而,我们得出的结论是,直接探测到的喷出物尘埃的质量增长到不超过10^(-4)Msun的几倍。我们还提供了证据,喷出物尘埃形成的共同运动的团块的固定大小。我们认为,大约两年后过去的爆炸,宽,盒形的光学线轮廓的外观是由于喷出物上的祖星周介质的影响,并随后形成一个凉爽,致密的外壳是负责后来上升的和平号通量。这项研究展示了一个典型的核心坍缩超新星及其前身可以产生和/或与尘埃颗粒相互作用的丰富,多方面的方式。这里提出的工作增加了越来越多的研究,不支持的论点,SNe负责大量的观测到的尘埃在高红移星系。

英文摘要:

We present mid-infrared (MIR) observations of the Type II-plateau supernova (SN) 2004et, obtained with the {\it Spitzer Space Telescope} between days 64 and 1406 past explosion. Late-time optical spectra are also presented. For the period 300-795 days past explosion, we argue that the spectral energy distribution of SN 2004et comprises (a) a hot component due to emission from optically thick gas, as well as free-bound radiation, (b) a warm component due to newly formed, radioactively heated dust in the ejecta, and (c) a cold component due to an IR echo from the interstellar-medium dust of the host galaxy, NGC 6946. There may also have been a small contribution to the IR SED due to free-free emission from ionised gas in the ejecta. We reveal the first-ever spectroscopic evidence for silicate dust formed in the ejecta of a supernova. This is supported by our detection of a large, but progressively declining, mass of SiO. However, we conclude that the mass of directly detected ejecta dust grew to no more than a few times 10^(-4)Msun. We also provide evidence that the ejecta dust formed in comoving clumps of fixed size. We argue that, after about two years past explosion, the appearance of wide, box-shaped optical line profiles was due to the impact of the ejecta on the progenitor circumstellar medium and that the subsequent formation of a cool, dense shell was responsible for a later rise in the MIR flux. This study demonstrates the rich, multi-faceted ways in which a typical core-collapse supernova and its progenitor can produce and/or interact with dust grains. The work presented here adds to the growing number of studies which do not support the contention that SNe are responsible for the large mass of observed dust in high-redshift galaxies.

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