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arXiv 1806.05097astro-ph.HE
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关于GW170817和银河双星中子星星族

On GW170817 and the Galactic Binary Neutron Star Population

Chris Pankow

摘要:

GW 170817/GRB 170817 A是一个短的伽马射线暴,由一个低质量的致密天体合并产生,是第一个在本星系邻域外发现的致密双星系统。从引力波测量,我们知道GW 170817有一个范围很广的合理组成质量,也取决于不太好的约束属性,如自旋和潮汐变形的组成恒星。kilonova光变曲线-电磁观测和随后的千诺瓦探测的喷出物特性的模型拟合提供了合并喷出物质量的值。这些值,当结合引力波测量不利于一个等质量的配置,与分歧的程度取决于动力学起源的喷出物质量的假设量。在我们银河系的范围内,已经有几个双中子星系统及其组成质量的测量结果。如果这些分布指示普遍分布,则GW 170817的组件质量的联合测量值代表离群值。这种张力不容易从物理学的论据中解决,因为形成双中子星的拟议路径通常不会产生非常不对称的对。即使考虑到与动态喷出物的总质量相关的不确定性,这种张力也表明星系中双星中子星质量的分布并不代表其他星系中的质量。

英文摘要:

GW170817/GRB170817A, a short gamma-ray burst arising from a low-mass compact object merger was the first multi-messenger discovery of a compact binary system outside the local galactic neighborhood. From gravitational-wave measurements, we know GW170817 has a wide range of plausible component masses, depending also on less well-constrained properties such as the spin and tidal deformability of the component stars. The kilonova light curve --- and hence the total ejecta mass from a given source --- depends on the relative contribution of dynamical ejecta and other sources such as disk winds. Electromagnetic observations and model fitting of the ejecta properties from the subsequent kilonova detection provided values of the ejecta mass from the merger. These values, when combined with the gravitational-wave measurement disfavors an equal-mass configuration, with the level of disagreement dependent on the assumed amount of ejecta mass of dynamical origin. Within the confines of our own galaxy, several binary neutron star systems along with measurements of their component masses have been made. If those distributions are indicative of a universal distribution, the joint measurement of the component masses of GW170817 represents an outlier. This tension is not easily resolvable from physical arguments, as the proposed pathways which form binary neutron stars do not often produce very asymmetrical pairs. Even accounting for the uncertainty associated with the total mass of the dynamical ejecta, this tension suggests that the distribution of binary neutron star masses in the galaxy is not indicative of those in other galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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