Formation and coalescence of relativistic binary stars: the effect of kick velocity
Formation and coalescence of relativistic binary stars: the effect of kick velocity
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DOI：
10.1093/mnras/288.1.245
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发表时间：
1997-02
影响因子：
4.8
通讯作者：
V. Lipunov;K. Postnov;M. Prokhorov
中科院分区：
文献类型：
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作者：
V. Lipunov;K. Postnov;M. Prokhorov
利用双星演化的现代情景的蒙特卡罗计算，并考虑磁化致密恒星的自旋演化(情景机器)，我们首次计算了具有不同伴星类型[OB星、白矮星(WD)、中子星(NS)、黑洞(BH)或行星]的银河系双星脉冲星的数量，假定新生NSS的踢速度的各种唯象分布。我们证明了双星脉冲星相对于单脉冲星的相对数量对平均踢球速度的强烈依赖性，并找到了最佳踢球速度为150-200公里的S-L。我们还研究了相对论双星(NS+NS，NS+BH，BH+BH)的合并率与踢速度的关系。我们指出，在银河系类型的星系中，BH+BH合并可能以每200000-500000年一次的速度发生，这取决于BH形成的参数。对于零后坐力，NS+NS的合并率RNS为每3000年1个；即使在最高的踢腿速度为400公里的S-L的情况下，RNS也下降到每10000年1个。由演化计算得出的合并率比仅基于双星脉冲星统计得到的合并率高两个数量级，这被认为是因为与NSS成对的可观测双星脉冲星只构成了双星NS系统总数的一小部分。所获得的合并率意味着对于广泛的参数范围，二进制BHS的预期检测率与二进制NS合并率相当，甚至高于二进制NS合并率。探测到合并事件的最终频率约为100赫兹，并对波形进行整形，将带来自然界中存在BHS的确凿证据。
Using Monte Carlo calculations of the modern scenario for binary stellar evolution, and taking account of the spin evolution of magnetized compact stars (the 'scenario machine'), we compute for the first time the number of galactic binary pulsars with different companion types [OB star, white dwarf (WD), neutron star (NS), black hole (BH), or planet] assuming various phenomenological distributions for kick velocities of newborn NSs. We demonstrate a strong dependence of the binary pulsar population fractions relative to single pulsars on the mean kick velocity, and find an optimal kick velocity of 150-200 km S-l. We also investigate the way in which the merging rates of relativistic binary stars (NS + NS, NS + BH, BH + BH) depend on the kick velocity. We show that the BH + BH merging may occur, depending on the parameters of BH formation, at a rate of one per 200000-500000 yr in a Milky Way-type galaxy. The NS + NS merging rate Rns is found to be 1 per '" 3000 yr for zero recoil, and decreases to one per 10 000 yr even for the highest kick velocities of 400 km S-l. That the merging rates derived from evolutionary calculations are higher, by two orders of magnitude, than those based on binary pulsar statistics only, is suggested to be the result of the fact that the observable binary pulsars in pairs with NSs form only a fraction of the total number of binary NS systems. The merging rates obtained imply an expected detection rate of binary BHs (by a gravitational wave detector) comparable with and even higher than the binary NS merging rate for a wide range of parameters. Detecting the final frequency of a merging event at about 100 Hz and the shaping of the waveforms would bring firm evidence of the existence of BHs in nature.