Neutron stars are invaluable tools for exploring stellar death, the physics of ultra-dense matter, and the effects of extremely strong magnetic fields. The observed population of neutron stars is dominated by the > 1000 radio pulsars, but there are distinct sub-populations that, while fewer in number, can have significant impact on our understanding of the issues mentioned above. These populations are the nearby, isolated neutron stars discovered by ROSAT, and the central compact objects in supernova remnants. The studies of both of these populations have been greatly accelerated in recent years through observations with the Chandra X-ray Observatory and the XMM-Newton telescope. First, we discuss radio, optical, and X-ray observations of the nearby neutron stars aimed at determining their relation to the Galactic neutron star population and at unraveling their complex physical processes by determining the basic astronomical parameters that define the population--distances, ages, and magnetic fields--the uncertainties in which limit any attempt to derive basic physical parameters for these objects. We conclude that these sources are 1e6 year-old cooling neutron stars with magnetic fields above 10e13 Gauss. Second, we describe the hollow supernova remnant problem: why many of the supernova remnants in the Galaxy have no indication central neutron stars. We have undertaken an X-ray census of neutron stars in a volume-limited sample of Galactic supernova remnants, and from it conclude that either many supernovae do not produce neutron stars contrary to expectation, or that neutron stars can have a wide range in cooling behavior that makes many sources disappear from the X-ray sky.ud
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机译:中子星是探索恒星死亡,超致密物质物理学以及超强磁场影响的宝贵工具。观察到的中子星群主要由> 1000个射电脉冲星组成,但是有不同的亚群,尽管数量较少,但会对我们对上述问题的理解产生重大影响。这些人口是由ROSAT发现的附近孤立的中子星,以及超新星残余中的中心致密天体。近年来,通过钱德拉X射线天文台和XMM-牛顿望远镜的观测,对这两个种群的研究大大加快。首先,我们讨论对附近中子星的无线电,光学和X射线观察,旨在确定它们与银河系中子星种群之间的关系,并通过确定定义种群的基本天文参数(距离,年龄和磁场-这些不确定性限制了为这些物体得出基本物理参数的任何尝试。我们得出的结论是,这些源是具有1e6年历史的冷却中子星,磁场强度超过10e13高斯。其次,我们描述了空心的超新星遗留问题:为什么银河中的许多超新星遗留物都没有指示中心中子星的迹象。我们在数量有限的银河系超新星残骸样本中对中子星进行了X射线普查,从中得出的结论是,要么许多超新星不会产生与预期相反的中子星,要么中子星的冷却范围很广使许多源从X射线天空消失的行为。 ud
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