Polarization as a probe of dusty environments around Type Ia supernovae: radiative transfer models for SN 2012dn
Polarization as a probe of dusty environments around Type Ia supernovae: radiative transfer models for SN 2012dn
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DOI：
10.1093/mnras/sty538
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发表时间：
2018-02
影响因子：
4.8
通讯作者：
T. Nagao;K. Maeda;M. Yamanaka
中科院分区：
文献类型：
--
作者：
T. Nagao;K. Maeda;M. Yamanaka
超新星周围星周介质的几何结构为理解其前身星的性质提供了重要的诊断依据。本文通过详细的三维辐射传输模拟研究了超新星候选者SN 2012 dn周围CS尘埃的性质。与SN 2012 dn检测到的近红外过量，我们表明，它有一个盘状的尘埃CS环境，其质量大致符合吸积白色矮星系统的分支（单一简并场景）。我们表明，一个类似的系统应产生偏振信号高达$\sim 8$ \%的$B$波段，根据观察方向，如果偏振观测。我们预测，最大极化是达到约$\sim 60$天后，$B$带的最大值。我们表明，时间和波长依赖的偏振信号，连同其他独特的功能，可以很容易地区分星际偏振和内在SN偏振。事实上，正常Ia型超新星（SNe Ia）观察到的小偏振度可以约束CS尘埃质量和分布的参数空间。因此，我们鼓励多波段偏振观测SNe Ia，特别是对离群值，包括SC-SNe的一些参数的单简并的情况下存在，但偏振数据是非常罕见的。
Geometry of circumstellar (CS) medium around supernovae (SNe) provides important diagnostics to understand the nature of their progenitors. In this paper, properties of CS dust around SN 2012dn, a super-Chandrasekhar candidate Type Ia supernova (SC-SN), have been studied through detailed three dimensional radiation transfer simulations. With the detected near-infrared excess from SN 2012dn, we show that it has a disk-like dusty CS environment whose mass is roughly consistent with a branch of an accreting white dwarf system (the single degenerate scenario). We show that a similar system should produce polarization signals up to $\sim 8$ \% in the $B$ band, depending on the viewing direction if polarimetric observation is performed. We predict that the maximum polarization is reached around $\sim 60$ days after the $B$-band maximum. We show that the temporal and wavelength dependence of the polarization signals, together with other unique features, can be easily distinguished from the interstellar polarization and intrinsic SN polarization. Indeed, the small polarization degree observed for normal Type Ia SNe (SNe Ia) can constrain a parameter space in the CS dust mass and distribution. We thus encourage multi-band polarimetric observations for SNe Ia, especially for outliers including SC-SNe for which some arguments for the single degenerate scenario exist but the polarization data are very rare so far.