论文标题
观察到的年轻脉冲星的速度分布II：完整PSR $π$的分析
The observed velocity distribution of young pulsars II: analysis of complete PSR$π$
论文作者
论文摘要
了解中子星的出生踢或出生速度对于理解大型二进制的演变以及双中性恒星形成至关重要。我们使用Verbunt等人发表的最大似然方法。分析Deller等人测量的新的大型视差数据集和适当的运动。该样本大约是以前可用的测量数量的三倍。对于完整的样本及其年轻部分（旋转年龄$τ<3 $ myr），我们发现双峰麦克斯韦分布比单个麦克斯韦人更好地描述了测得的视差和正确的运动，概率分别为99.3和95.0％。 Bimodal Maxwellian分布有三个参数：低速和高速模式的低速脉冲星和分布参数$σ_1$和$σ_2$。对于完整的示例，这些参数如下：$ 42 _ { - 15}^{+17} $％，$σ_1= 128 _ { - 18}^{+22} $ 22} $ km s $ s $ s $^{ - 1} $ and $σ_2= 298 \ pm pm 28 $ 28 $ km s $ s $ s $ s $^{-1} $。 For younger pulsars, which are assumed to represent the natal kick, these parameters are as follows: $20_{-10}^{+11}$ per cent, $σ_1=56_{-15}^{+25}$ km s$^{-1}$ and $σ_2=336\pm 45$ km s$^{-1}$.在年轻人口中，$ 5 \ pm 3 $ plsars的速度小于60 km s $^{ - 1} $。考虑到现实的观察性选择，我们对该方法进行了多个蒙特卡洛测试。我们发现该方法可靠地估算出生踢分布的所有参数。速度分析的结果对银河脉冲星分布的比例长度的确切值敏感。
Understanding the natal kicks, or birth velocities, of neutron stars are essential for understanding the evolution of massive binaries as well as double neutron star formation. We use maximum likelihood methods as published in Verbunt et al. to analyse a new large dataset of parallaxes and proper motions measured by Deller et al. This sample is roughly three times larger than number of measurements available before. For both the complete sample and its younger part (spin-down ages $τ< 3$ Myr), we find that a bimodal Maxwellian distribution describes the measured parallaxes and proper motions better than a single Maxwellian with probability of 99.3 and 95.0 per cent respectively. The bimodal Maxwellian distribution has three parameters: fraction of low-velocity pulsars and distribution parameters $σ_1$ and $σ_2$ for low and high-velocity modes. For a complete sample, these parameters are as follows: $42_{-15}^{+17}$ per cent, $σ_1=128_{-18}^{+22}$ km s$^{-1}$ and $σ_2 = 298\pm 28$ km s$^{-1}$. For younger pulsars, which are assumed to represent the natal kick, these parameters are as follows: $20_{-10}^{+11}$ per cent, $σ_1=56_{-15}^{+25}$ km s$^{-1}$ and $σ_2=336\pm 45$ km s$^{-1}$. In the young population, $5\pm 3$ per cent of pulsars has velocities less than 60 km s$^{-1}$. We perform multiple Monte Carlo tests for the method taking into account realistic observational selection. We find that the method reliably estimates all parameters of the natal kick distribution. Results of the velocity analysis are weakly sensitive to the exact values of scale-lengths of the Galactic pulsar distribution.
