Neutrino-driven winds from neutron star merger remnants
Neutrino-driven winds from neutron star merger remnants
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DOI：
10.1093/mnras/stu1352
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发表时间：
2014-05
影响因子：
4.8
通讯作者：
A. Perego;S. Rosswog;R. Cabezón;O. Korobkin;R. Kaeppeli;A. Arcones;M. Liebendoerfer
中科院分区：
文献类型：
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作者：
A. Perego;S. Rosswog;R. Cabezón;O. Korobkin;R. Kaeppeli;A. Arcones;M. Liebendoerfer
我们对中子星合并后产生的中微子驱动的风进行了详细的三维流体力学研究。我们的模拟是用牛顿、欧拉程序FISH进行的，并增加了一个详细的、光谱中微子泄漏方案，该方案考虑了光学薄条件下中微子吸收产生的热量。与Dessart等人早期的二维研究一致。(2009)，我们发现在合并后100毫秒内，沿着原来的双星旋转轴吹出了一股强烈的重子风。我们计算了3：5×10~3M的出射质量下限，这个下限足以与重元素核合成相关。不同风区的物理性质有显著差异。例如，由于更强的中微子辐射，极地地区的电子比例比低纬度地区的要大得多。这与核合成有关：极地抛射物产生从A80到约130的有趣的r过程贡献，而更富中子的低纬度部分还产生直到A195附近的第三个r过程峰值的元素。我们还计算了由风中的放射性提供动力的电磁瞬变的性质，以及由动态喷出产生的马克诺瓦瞬变。在高纬度(极地)地区产生的紫外线/光学瞬变可以达到1041erg S 1的光度，光学光度的峰值在1天左右，测辐射光度的峰值在0.3天左右。低纬地区由于受到高不透明度重元素的污染，产生更暗和更多的红色信号，在光学和红外信号中2天后达到顶峰。我们的数值实验表明，根据风的电磁瞬变来推断超大质量中子星到黑洞的坍塌时间尺度是不可能的，至少对于大于风产生时间尺度的坍塌时间尺度是如此。
We present a detailed, three-dimensional hydrodynamic study of the neutrino-driven winds that emerge from the remnant of a neutron star merger. Our simulations are performed with the Newtonian, Eulerian code FISH, augmented by a detailed, spectral neutrino leakage scheme that accounts for heating due to neutrino absorption in optically thin conditions. Consistent with the earlier, two-dimensional study of Dessart et al. (2009), we nd that a strong baryonic wind is blown out along the original binary rotation axis within 100 milliseconds after the merger. We compute a lower limit on the expelled mass of 3:5 10 3 M , large enough to be relevant for heavy element nucleosynthesis. The physical properties vary signicantly between dierent wind regions. For example, due to stronger neutrino irradiation, the polar regions show substantially larger electron fractions than those at lower latitudes. This has its bearings on the nucleosynthesis: the polar ejecta produce interesting r-process contributions from A 80 to about 130, while the more neutron-rich, lower-latitude parts produce in addition also elements up to the third r-process peak near A 195. We also calculate the properties of electromagnetic transients that are powered by the radioactivity in the wind, in addition to the \macronova" transient that stems from the dynamic ejecta. The high-latitude (polar) regions produce UV/optical transients reaching luminosities up to 10 41 erg s 1 , which peak around 1 day in optical and 0.3 days in bolometric luminosity. The lower-latitude regions, due to their contamination with high-opacity heavy elements, produce dimmer and more red signals, peaking after 2 days in optical and infrared. Our numerical experiments indicate that it will be dicult to infer the collapse time-scale of the hypermassive neutron star to a black hole based on the wind electromagnetic transient, at least for collapse time-scales larger than the wind production time-scale.