论文标题
在合并双中子星的延迟时间
On the delay times of merging double neutron stars
论文作者
论文摘要
双中子星（DNS）的合并速率对许多天体物理问题具有很大的影响，包括对引力波信号的解释，短伽马射线爆发（GRB）以及星系中恒星的化学特性。这种速率取决于合并事件的延迟时间（DDT）的分布。在本文中，我们从控制其演变的时钟的特征中得出了合并DNS的理论DDT。我们表明，DDT的形状受一些关键参数的控制，主要是DNS系统分离时的下限和斜率。通过一种参数方法，我们研究了从短grb的宇宙速率和银河系恒星中的欧洲比率的观察力约束，这是爆炸产物的示踪剂。我们发现，局部DNS合并的速率要求大约1％的中子星祖细胞生活在二元系统中，这结束了它们在哈勃时期内合并DNS的演变。短期GRB的红移分布尚未对DDT的形状产生强大的限制，尽管最佳拟合模型具有浅滴滴室。银河系中的化学模式除了合并DNS的产品外，恒星还需要Europium的附加来源，这削弱了DDT的相关要求。目前，这两个约束都可以与相同的DDT匹配以合并DNS。
The merging rate of double neutron stars (DNS) has a great impact on many astrophysical issues, including the interpretation of gravitational waves signals, of the short Gamma Ray Bursts (GRBs), and of the chemical properties of stars in galaxies. Such rate depends on the distribution of the delay times (DDT) of the merging events. In this paper we derive a theoretical DDT of merging DNS following from the characteristics of the clock controlling their evolution. We show that the shape of the DDT is governed by a few key parameters, primarily the lower limit and the slope of the distribution of the separation of the DNS systems at birth. With a parametric approach we investigate on the observational constraints on the DDT from the cosmic rate of short GRBs and the Europium to Iron ratio in Milky Way stars, taken as tracer of the products of the explosion. We find that the local rate of DNS merging requires that about 1 percent of neutron stars progenitors live in binary systems which end their evolution as merging DNS within a Hubble time. The redshift distribution of short GRBs does not yet provide a strong constraint on the shape of the DDT, although the best fitting models have a shallow DDT. The chemical pattern in Milky Way stars requires an additional source of Europium besides the products from merging DNS, which weakens the related requirement on the DDT. At present both constraints can be matched with the same DDT for merging DNS.
