| 其他摘要 | This paper is a theoretical doctorial thesis on the study of gravitational wave (GW) radiation sources. GW is a natural consequence of Einstein's theory of gravity (``general relativity"), and minute distortions of space--time. Gravitational Wave Astronomy is an emerging branch of observational astronomy which aims to use GWs to collect observational data about objects such as neutron stars and black holes, about events such as supernovae and about the early universe shortly after the big bang. The Laser Interferometer Gravitational-Wave Observatory or LIGO, a joint project between Massachusetts Institute of Technology (MIT) and California Institute of Technology (Caltech) is spearheading with equally ambitious projects such as VIRGO, TAMA 300 and GEO 600. Specially, the LISA is a planned space based GW observatory at low frequency with the launch date in the 2018+ time frame. This field will evolve to become an established component of 21st century multi-messenger astronomy, and will stand shoulder-to-shoulder with gamma-ray, x-ray, optical, infrared and radio astronomers in exploring the cosmos。In this thesis, we state recent theoretical study on GW sources, and present the results of our studies on the field. The different frequency ranges of the GW detectors will respectively correspond to different observation sources. The main purpose of this paper is to explore the different GW sources with respect to the ground or space detectors. Specially, we focus on the compact binaries as GW sources. These studies not only help us to understand the waveform of different sources, but also at some level can allow us to characterize the range of possible GW signals. By means of a population synthesis code, we investigate close double white dwarfs (CDWDs), AM CVn stars, ultra-compact X-ray binaries(UCXBs), double neutron stars, double stellar black holes as GW sources, respectively. For instance, we used population synthesis models to create a population of compact double white dwarfs (CDWDs) and discussed the the effect of these binaries as both foreground noise and resolvable sources for the LISA GW detector. We also look in more detail at the systems that form the resolvable sources. In particular, we show istributions of the primary and secondary masses, which indicate whether a binary member is a helium or carbon-oxygen white dwarf, as well as chirp masses and orbital periods for the CDWDs that are ervable with LISA, and we compare these distributions to a sample of observed systems. In addition, we discuss the birth rates for the three relevant formation channels and the contribution of each channel to the observable CDWDs. At the same time, we also analyze other GW sources, such as pulsar, gravitational collapse of core, double super--massive black holes. We hope that our studies can characterize the ground and space detectors in the future. |
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