Studying the diversity of Type Ia supernovae in the ultraviolet: comparing models with observations
Studying the diversity of Type Ia supernovae in the ultraviolet: comparing models with observations
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DOI：
10.1111/j.1365-2966.2012.21928.x
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发表时间：
2012-08
影响因子：
4.8
通讯作者：
E. Walker;S. Hachinger;P. Mazzali;R. Ellis;M. Sullivan;A. Gal-yam;D. Howell
中科院分区：
文献类型：
--
作者：
E. Walker;S. Hachinger;P. Mazzali;R. Ellis;M. Sullivan;A. Gal-yam;D. Howell
在紫外线（UV）中，Ia型超新星（SNe Ia）的性质比在光学中表现出更大的多样性。使用固定蒙特卡罗辐射传输代码，在最大光下创建了光谱网格，改变了SN喷射物外层的放热光度和金属量。然后将该模型网格与高红移SNe Ia样本进行比较，以测试观察到的多样性是否可以仅用光度和金属丰度变化来解释。宽频带紫外通量的色散和近似恒定光谱下的颜色可以很容易地通过模型网格匹配。特别地，UV1 - b颜色被发现是外喷射物金属含量的良好示踪剂，这可能反过来反映SN祖先的金属丰度。这些模型在再现其他观察到的趋势方面不太成功，例如关键紫外线特征的波长，这是由光学或中间波段光度指数的反向荧光光子主导的。这可以用这些详细的可观测物对相对丰度的适度变化的更大敏感性来解释。具体来说，没有单一的因素对观察到的趋势负责。由于其复杂的起源，这些趋势似乎不是光度或金属丰度的良好指标。
In the ultraviolet (UV), Type Ia supernovae (SNe Ia) show a much larger diversity in their properties than in the optical. Using a stationary Monte Carlo radiative transfer code, a grid of spectra at maximum light was created varying bolometric luminosity and the amount of metals in the outer layers of the SN ejecta. This model grid is then compared to a sample of high-redshift SNe Ia in order to test whether the observed diversities can be explained by luminosity and metallicity changes alone. The dispersion in broad-band UV flux and colours at approximately constant optical spectrum can be readily matched by the model grid. In particular, the UV1 − b colour is found to be a good tracer of metal content of the outer ejecta, which may in turn reflect on the metallicity of the SN progenitor. The models are less successful in reproducing other observed trends, such as the wavelengths of key UV features, which are dominated by reverse fluorescence photons from the optical, or intermediate-band photometric indices. This can be explained in terms of the greater sensitivity of these detailed observables to modest changes in the relative abundances. Specifically, no single element is responsible for the observed trends. Due to their complex origin, these trends do not appear to be good indicators of either luminosity or metallicity.