Extreme Physics with Pulsars and Radio Transients

像中子星这样的致密天体提供了探索广泛的基本物理问题的机会。许多中子星发出灯塔状的射电波束，这可能会在每一次自转中击中地球一次，从而导致我们将这颗恒星标记为脉冲星。自转速度最快的脉冲星每秒自转数百次，在短时间尺度上可以与原子钟的稳定性相媲美。一组散布在天空中的毫秒脉冲星可以用来直接探测经过地球附近的引力波。据预测，这些引力波的主要来源是作为最近合并的星系中心的两对超大质量黑洞，这与激光干涉引力波天文台(LIGO)最近探测到的恒星质量黑洞具有很强的互补性。这里提出的脉冲星定时阵列研究将通过改进目前的数据简化方法并引入全新的数据来提高北美引力波纳赫兹天文台(NANOGrav)的效率，这些数据将解决星际介质变化引起的系统学问题。这些数据将来自正在不列颠哥伦比亚省彭蒂顿建造的加拿大氢强度测绘实验(CHME)望远镜。与最初的宇宙学任务同时，CHINE将提供关于北方NANOGrav脉冲星的每日数据，使我们能够比目前更详细地模拟星际介质中的变化，并提供对更高频率的NANOGrav数据的修正。该项目将加快NANOGrav探测引力波的时间表。CHAME还将提供许多其他有趣的脉冲星的密集数据集，包括相对论双星，这是该研究小组的另一个长期兴趣。CHAME在解决仍然神秘的快速射电暴(FRB)方面拥有更多希望。这些是射电发射的单尖峰，几乎可以肯定是起源于河外，用一些现存的最大的射电望远镜可以看到。这些来源中的一个现在被认为是重复的，但目前尚不清楚是否有两类来源。爆炸的原因尚不清楚--事实上，目前发表的理论比爆发更多--但推断的亮度和较短的时间尺度表明，很可能涉及中子星等致密天体。有了CHINE上专门的第二台仪器，我们预计每天可以探测到数十次FRB；极大地改进的统计数据将限制模型，并可能有助于更好地定位爆发，以识别宿主星系。

Compact stellar objects such as neutron stars offer the opportunity to probe a wide range of fundamental physics problems. Many neutron stars emit lighthouse-like radio beams, which may hit the Earth once per rotation and cause us to label the star a pulsar. The fastest-spinning pulsars rotate several hundred times per second and can rival the stability of atomic clocks on short timescales. An array of these millisecond pulsars, spread across the sky, can be used to make a direct detection of gravitational waves passing near the Earth. The main sources of these gravitational waves is predicted to be pairs of supermassive black holes as the centres of galaxies that have recently undergone mergers, highly complementary to the stellar-mass black holes recently detected by the Laser Interferometric Gravitational-wave Observatory (LIGO). The pulsar timing array research proposed here will enhance the effectiveness of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), by improving the current data-reduction methods and by bringing in entirely new data which will address systematics due to variations in the interstellar medium. These data will come from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope under construction in Penticton, B.C. Simultaneously with its original cosmology mission, CHIME will provide daily data on the Northen NANOGrav pulsars, allowing us to model the variations in the interstellar medium in more detail than currently possible and providing corrections to the higher-frequency NANOGrav data. This project will accelerate the timeline for NANOGrav to make a detection of gravitational waves. CHIME will also provide dense data sets on numerous other interesting pulsars, including relativistic binaries, which are another long-term interest of this research group.******CHIME holds still more promise, for tackling the still-mysterious Fast Radio Bursts (FRBs). These are single spikes of radio emission, almost certainly extragalactic in origin, seen with some of the largest radio telescopes in existence. One of these sources has now been seen to repeat, but it is unclear at present whether there are two classes of source. What causes the bursts is still unknown-- in fact there are more published ideas than bursts at present -- but the inferred brightness and short timescale indicate that the involvement of a compact object such as a neutron star is likely. With a dedicated second instrument on CHIME, we expect to detect several tens of FRBs per day; the vastly improved statistics will constrain models and may help to localize the bursts well enough to identify host galaxies.