The Radio Lifetime of Supernova Remnants and the Distribution of Pulsar Velocities at Birth
The Radio Lifetime of Supernova Remnants and the Distribution of Pulsar Velocities at Birth
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DOI：
10.1086/175038
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发表时间：
1994-07
期刊：
影响因子：
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通讯作者：
D. Frail;W. Goss;J. Whiteoak
中科院分区：
文献类型：
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作者：
D. Frail;W. Goss;J. Whiteoak
我们对三颗年轻脉冲星周围的场进行了 VLA 图像，从而发现了两颗新的超新星遗迹，并确认了第三颗。我们认为，至少在两种情况下，也许在第三种情况下，脉冲星与这些超新星遗迹有物理联系。对所有已知年轻脉冲星的回顾表明，大多数都与超新星遗迹有关。我们发现，超新星遗迹演化成的星际介质的典型密度为 0.2 cm$^{-3}$，而不是其他研究计算出的低值 0.01 cm$^{-3}$，这导致超新星遗迹的射电寿命显着延长。超新星遗迹的形态和脉冲星的位置都表明这些年轻脉冲星大多数诞生时都具有很大的横向速度（$\sim$500 km s$^{-1}$）。脉冲星速度分布中的这种高速度平均值似乎是脉冲星群出生时的一般属性，由于选择效应，在自行研究中没有看到。我们探讨了这一结果的含义，因为它与这些速度的起源和脉冲星的银河分布有关。高速脉冲星可以在非常短的时间尺度内逃离超新星遗迹，与遗迹的寿命相当，甚至可能在延长遗迹的可观测射电寿命方面发挥作用。很大一部分将能够逃离银河系圆盘，产生更多的光环群体。
We have made VLA images of the fields around three young pulsars which have resulted in the discovery of two new supernova remnants and confirmation of a third. We argue that, in at least two cases and perhaps the third, the pulsars are physically associated with these supernova remnants. A review of all known young pulsars shows that the majority are associated with supernova remnants. We show that the typical density of the interstellar medium into which the supernova remnants are evolving has a density of 0.2 cm$^{-3}$ instead of the low value of 0.01 cm$^{-3}$ which had been calculated from other studies, and results in a considerably longer radio lifetime for supernova remnants. Both the morphology of the supernova remnants and the location of the pulsars imply that most of these young pulsars are born with large transverse velocities ($\sim$500 km s$^{-1}$). This high velocity mean in the distribution of pulsar velocities appears to be a general property of the pulsar population at birth, not seen in proper motion studies, due to selection effects. We explore the implications of this result as it relates to the origin of these velocities and the galactic distribution of pulsars. High velocity pulsars can escape their supernova remnant in a very short timescale, comparable to the lifetime of the remnant and may even play a role in extending the observable radio lifetime of the remnant. A significant fraction will be capable of escaping the disk of the Galaxy, producing an extended halo population.