Study Of Gravitational Wave Sources And Standard Sirens

Gravitational waves are ripples of spacetime.The era of gravitational wave（GW）astronomy begins with the Laser Interferometry Gravitaitional-Wave Observatory（LIGO）detection of GW150914,a signal from the inspiralling and merger of a black hole binary system,which directly confirmed the prediction of general relativity in 1916.Further,the GW170817/GRB 170817A,a GW signal from binary neutron star merger and its electromagnetic（EM）counterparts,heralds the epoch of multi-messenger gravitational wave astronomy.In Chapter 1,we look back to the GW theory and the history of GW detections,introduced various kinds of GW sources,which have different frequencies.GW not only plays a significant role in studying gamma-ray bursts（GRBs）,kilonovae,and neutron stars（NSs）,but also provides a potential tool to learning comology with.With the luminosity distance fitted from the GW waveform and the redshift information from the host galaxy,GW can be treated as standard sirens to do researches in cosmology.We summarize the current study of GW standard sirens,including the independent measurement of Hubble constant（H₀）.In Chapter 2,we study the statistical properties of binary neutron star mergers,including the merger locations’offsets from galaxy centers,the delay time and merger distribution and the evolution of merger rate as a function of redshift,using new version of population synthesis code BSE.In many models of FRBs,the BNS merger itself or its outcome—a stable NS—are central engines of FRBs.Recently,the localized non-repeating FRBs such as FRB 180924 and FRB 190523 have large offsets relative to their host galaxies,which supports that FRBs are related to BNS mergers.With the population synthesis,we found that the offsets of BNS mergers can be up to 30 kpc,which agrees with the observations of localized FRBs.In Chapter 3,we conceive of a new kind of GW standard siren from extreme mass ratio inspirals（EMRIs）and the related EM signals.The EMRI is the inspiral of compact object into supermassive black hole（SMBH）,which is the main scientific goal of space-borne GW detectors such as e LISA.Traditionally,EMRIs are thought to have no EM counterparts.However,we put up with a mechanism for observing both EMRI and possible EM precursor in which a”onion-like”massive star gets tidally stripped by an SMBH of outer layers and the subsequent inspiral of the compact C-O core provides EMRI signal.With certain initial semi-major axis and eccentricity,we can detect an EMRI at the same location as a previously observed TDE.If they are proved to have the same origin,we have a new version of standard sirens,which can not only serve as a cosmological proble,but also help identify the host galaxy of EMRI.In Chapter 4,we propose to use GW standard sirens to probe the peculiar velocities of galaxies in local universe.The radial peculiar velocity can be calculated via vobs,r=cz-H₀dp.However,since vobs,r obtained in this way strongly depends on H₀,we need an independently measured H₀ because of the H₀ tension.Therefore,we compare the radial peculiar velocities from GW observations with those reconstructed from PSCz galaxy survey,which can constrain H₀.Besides,the reconstructed peculiar velocity depends on parameterβ,so we fit H₀ andβsimultaneously using Markov chain Monte Carlo（MCMC）.With the distance uncertainty of GW events down to 0.1%by future detectors,the uncertainty of the peculiar velocity can be reduced to 10 km s^-1at 100Mpc.We find that dozens of GW events with EM counterparts can provide a precision of0.5%for H₀ and 0.6%for growth rate of structure respectively with the third-generation ground-based GW detectors,which can reconcile the H₀ tension and determine the origins for cosmic accelerating expansion.In Chapter 5,we use standard sirens to calibrate the luminosity correlations of GRBs.These correlations are promising tools with which to probe high redshift universe in spite of the circularity problem.Common solutions such as calibrating with SNe Ia will introduce the systematics while standard sirens will not.Based on the assumption that objects of the same redshift have the same luminosity distance,the d L of GRBs are obtained through interpolation.We use mock GW catalog and observed GRB samples to calibrate Amati relation and Ghirlanda relation.Combined with Pantheon SNe sample,we can constrain cosmological models.In the last,we give a brief discussion of future gravitational wave detectors,both ground-based and space-based and show the prospects for gravitational wave astronomy.