双中子星并合中r过程核合成的光谱识别
高能天体物理现象
2017-10-19 v1
摘要
两颗中子星的并合预计将产生三种主要可探测现象：伽马射线短暴、引力波信号，以及由快中子俘获（r过程）合成大量极重元素所驱动的暂现光学/近红外源。这类暂现源被称为'巨新星'或'千新星'，被认为是金和铂等稀有元素的产生中心。截至目前最有力的千新星证据是在红移 的短伽马射线暴余辉中观测到的极暗近红外再增亮，尽管已有报道指出存在更蓝的事件。在此，我们报告了对与引力波源GW 170817和伽马射线暴GRB 170817A相关联的千新星的光谱识别，并描述了其物理性质。该千新星与地球距离约40 Mpc，位于一个星系中。利用一系列覆盖紫外到近红外波段的地面天文台光谱，我们发现该千新星以约0.2倍光速的速度快速膨胀的抛射物为特征，其光谱特征与当前模型预测相似。抛射物早期光学厚，速度约为0.2倍光速，仅在1.5天内即达到约50天文单位的半径。随着抛射物膨胀，光谱连续谱上出现宽吸收线，表明由并合后快速运动动力学抛射物和两个较慢（0.05倍光速）风区中发生的核合成所产生的原子种类。与光谱模型的比较表明，该并合抛射出了0.03-0.05太阳质量的物质，包括高不透明度的镧系元素。
引用
@article{arxiv.1710.05858,
title = {Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger},
author = {E. Pian and P. D'Avanzo and S. Benetti and M. Branchesi and E. Brocato and S. Campana and E. Cappellaro and S. Covino and V. D'Elia and J. P. U. Fynbo and F. Getman and G. Ghirlanda and G. Ghisellini and A. Grado and G. Greco and J. Hjorth and C. Kouveliotou and A. Levan and L. Limatola and D. Malesani and P. A. Mazzali and A. Melandri and P. Moller and L. Nicastro and E. Palazzi and S. Piranomonte and A. Rossi and O. S. Salafia and J. Selsing and G. Stratta and M. Tanaka and N. R. Tanvir and L. Tomasella and D. Watson and S. Yang and L. Amati and L. A. Antonelli and S. Ascenzi and M. G. Bernardini and M. Boer and F. Bufano and A. Bulgarelli and M. Capaccioli and P. G. Casella and A. J. Castro-Tirado and E. Chassande-Mottin and R. Ciolfi and C. M. Copperwheat and M. Dadina and G. De Cesare and A. Di Paola and Y. Z. Fan and B. Gendre and G. Giuffrida and A. Giunta and L. K. Hunt and G. Israel and Z. -P. Jin and M. Kasliwal and S. Klose and M. Lisi and F. Longo and E. Maiorano and M. Mapelli and . Masetti and L. Nava and B. Patricelli and D. Perley and A. Pescalli and T. Piran and A. Possenti and L. Pulone and M. Razzano and R. Salvaterra and P. Schipani and M. Spera and A. Stamerra and L. Stella and G. Tagliaferri and V. Testa and E. Troja and M. Turatto and S. D. Vergani and D. Vergani},
journal= {arXiv preprint arXiv:1710.05858},
year = {2017}
}
备注
version accepted for publication in Nature. Some minor changes are expected with respect to the journal version