Study Of Kilonova And Supernova Driven By Magnetized Disk Wind

Gamma-ray bursts（GRBs）are the most violent explosions in the universe.The study of gamma-ray bursts has been going on for more than half a century since their discovery in the middle of the last century,during which many significant advances for understanding the physics of GRBs have been made.For example,the GRBs can be divided into two categories,long gamma-ray bursts（LGRBs）and short gamma-ray burst（SGRBs）.The LGRBs lasts more than two seconds,while it of SGRBs last less than 2s.It is widely accepted that the LGRBs are arisen from the death of the massive stars,and associate with type Ic supernovae（SN）.It has been suggested that SGRBs are orignated from the merger of two compact star,and that they are associated with an optical transient event,which is so-called kilonove.The association between SGRBs and kilonove was proofed by the disovery of the graviation wave from the merger of the two neutron stars in 2017.The observation of LGRB-SN and SGRB-kilonova association is very important for the study of stellar evolution,element synthesis and equation of state（EOS）of neutron star.The kilonova is powered by radioactive decay heating the the enjected matter ejected by the merger of two compact star.The traditional model of the kilonova emission has considered only the nuclear reaction.However,given that the merger of compact stars leaves a central object,the continued activity of the central compact object also provides an additional energy source for the kilonova.Observational evidence from the GRB also suggests that the continuous energy injection from the central compact object affects the afterglow behavior of the GRB.In this thesis,we mainly study the effect of disk wind generated by black hole accretion on kilonova when the merger product is a black hole.At the same time,we also study the properties of the central compact object left from the perspective of the electromagnetic observation of the gamma-ray burst and the kilonova.In addition,we also study the black hole as the central engine of the LGRB and supernovae.The observations of the LGRBs have accumulated the evidence that in the shock driven by the disk wind,enough ⁵⁶Ni can be synthesized to produce a bright supernova.Using a large observational samples of long GRBs and supernovae,we can limit the parameters of the central engine of the black hole.This thesis is organized as follows:Firstly,we introduce the history of GRBs,including theory and observation for the central engine and the progenitor.Then we introduce the development history of kilonova,including the latest research progress from the perspective of theoretical model and observation.The cooperative observations for gravitational waves,SGRBs and kilonova provide a perfect ending story of the progenitors stars of the GRB.Finally,a briefly introduce the supernovae associated with long GRBs.Chapter 2-5 are my works during my doctoral period.we discuss the kilonova and supernova model with magnetized disk wind.A merger of two compact objects is very likely to leave a stellar-mass black hole and accretion disk.The disk wind generated by t the accretion process provide additional energy to kilonova,and at the same time it will collimate the jet,which is required for GRB in the polar direction.Our work connect the connection between GRB and kilonova from the perspective of the central engine and fill the research blank in this field to some extent.In addition,we propose a model of ⁵⁶Ni synthesis in the shock wave driven by disk wind,which can explain the supernovae associated with long GRBs.In Chapter 3,we apply our kilonova model to individual source.We use a hybrid energy model of disk wind and radioactive decay to explain the optical electromagnetic counterpart AT2017gfo of GW170817.Our model not only provides additional energy for kilonova source indicated by the light curve of AT2017gfo,but also provides a reasonable explanation for the low luminosity of GRB 170817A.To further explore the effects of the central engine on GRBs and kilonova,we focus on peculiar source GRB 160821B with a bright kilonove component,for which deep multi-wavelength observations were carried out.By analyzing the multi-wavelength data,we found that the progenitor of GRB 160821B is a binary neutron star that merged to form a magnetar,and then the magnetar rotates slowly and collapsed into a black hole due to the spin-down.The fall-back accretion on the new-born black hole provides the energy for the afterglow and kilonova.The significance of this event is that even in the absence of gravitational wave detection,the multiband electromagnetic radiation of gamma-ray bursts and kilonova can be used to determine the merger products.In Chapter 5,we discuss on the LGRBs and its association with the supernovae.We discuss the possibility of ⁵⁶Ni synthesis in the shock driven by the disk wind.The main aim of this work is to explain the energy source for all the long bursts and its associated supernovae within the framework of the black hole central engine model.We also constrain the parameters of the black hole’s central engine.Finally,we summarize the work during the Doctoral period.We discuss the limitations of the present research works and the prospect of future research.