| 其他摘要 | The direct detection of gravitational-wave (GW) opens a new era for the astronomical observation. Since the first binary black hole (BBH) merger was detected by Advanced LIGO in 2015, many GW events associated with merging BBH or binary neutron star (BNS) have been confirmed. With the the next-generation ground-based GW detectors and space GW detectors (especially, LISA) put into use, the GW associated with double compact objects merger, their host galaxies will be found, and the redshift evolution of the BBH merger will be reconstructed to very high redshift .These GW observations are helpful to understand the evolution of massive stars, the formation and the evolution of galaxy. In this thesis, we state recent study on GW and make use of Newman-Penrose forula to study GW equation and get its expression under most general static and axial symmetric space-time. Then especially we focus on BBH merger/ binary neutron stars (BNS) mergers and their host galaxies, and present the results of our studies on the field . We make use of BSE code to produce a lot of sample about BBH/BNS merger, and compute their merger rate. Under different stellar remnant mass recipe and supernova kick velocities, these samples have different properties. Then we construct a phenomenological model of the cosmic gravitational-wave (GW) merger events by using BSE binary-star evolution code and some fitting formulas ( such as, the relation between maximum black hole mass and metallicity in a stellar population). By using Bayesian analysis method and the observations from the advanced LIGO and Virgo, we obtain the relevant parameters of the phenomenological model (such as the maximum black hole mass is 93 solar mass).Combining the above model results with the galaxy catalogue given by the EMERGE, we present the probability of binary black holes (BBH) and binary neutron stars (BNS) mergers as functions of stellar mass, metallicity, specific star formation rate (sSFR) and age for galaxies with redshift less than 0.1. We find the normalized number probability of a merger event varying with log10_(sSFR/yr-1)$ for galaxies with z less than 0.1 is different from the previous studies, that is, two peaks exist in this work while there is only one peak (log10(sSFR/yr-1)=-10) in the previous work. The sSFR value corresponding the new peak is log10(sSFR/yr-1)=-12 and in line with the value ( log10(sSFR/yr-1)=-12.65) of NGC4993, the host galaxy of BNS merger event GW170817. The new peak is caused by the today's quenched galaxies, which give a large contribution to the total SFR at high redshift in the EMERGE empirical galaxy model. Moreover, we find that the BNS mergers are most likely detected in the galaxies with age near 11Gyr, which is greater than previous results (6-8Gyr) and close to the age of NGC 4993, i.e. 13.2Gyr.Because observed dada of the host galaxies of BNS mergers are rare, we compare our mode with host galaxies of short-duration gamma-ray bursts. These observed data is well fitted by our model. Our model can overlap the observed data when it varies with different times, but it is't accurate to fit the redshift of short-duration gamma-ray bursts. If we want to answer this problem, we not only need to improve the stellar evolution model , but also improve the galaxy model to describe downsizing accurately. |
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