We present the broadband numerical modeling of afterglows for two remarkably bright long gamma-ray bursts(GRBs),GRB 050820 A and GRB 070125,with a wide range of observations from the radio band to the X-ray band.In ou...We present the broadband numerical modeling of afterglows for two remarkably bright long gamma-ray bursts(GRBs),GRB 050820 A and GRB 070125,with a wide range of observations from the radio band to the X-ray band.In our work,we fit light curves and constrain physical parameters using a standard forward shock model from the afterglowpy Python package,considering different jet structures and the jet lateral expansion.For GRB 050820 A,the constrained jet is close to a top-hat jet with an extremely small half opening angle of about 0.015 rad,and the circumburst matter density is as small as 10^(-7)cm^(-3),which suggests that this peculiar long GRB might originate from metal-poor stars with low mass-loss rates.To explain the late time optical light curves of GRB 070125,the effects of the lateral expansion and the participation factor of electrons that are accelerated by the shock have to be taken into account.The constrained results for GRB 070125 show that the jet is also close to a top-hat jet with a half opening angle of about 0.1 rad,the viewing angle is about 0.05 rad,the circumburst density is about 10 cm^(-3),and the participation factor is about 0.1.The jet energy of the two bursts is required to be~1051–1052 erg,which can be produced by a millisecond magnetar or a hyper-accreting black hole.展开更多
Combining observations of multi-messengers help in boosting the sensitivity of astrophysical source searches,and probe various aspects of the source physics.In this chapter we discuss how LHAASO observations of very h...Combining observations of multi-messengers help in boosting the sensitivity of astrophysical source searches,and probe various aspects of the source physics.In this chapter we discuss how LHAASO observations of very high energy(VHE)gamma rays in combination with telescopes for the other messengers can help in solving the origins of VHE neutrinos and galactic and extragalactic cosmic rays.展开更多
基金the National Natural Science Foundation of China(NSFC,Grant Nos.12073080,11933010,11921003 and 12173091)the Chinese Academy of Sciences via the Key Research Program of Frontier Sciences(No.QYZDJ-SSW-SYS024)。
文摘We present the broadband numerical modeling of afterglows for two remarkably bright long gamma-ray bursts(GRBs),GRB 050820 A and GRB 070125,with a wide range of observations from the radio band to the X-ray band.In our work,we fit light curves and constrain physical parameters using a standard forward shock model from the afterglowpy Python package,considering different jet structures and the jet lateral expansion.For GRB 050820 A,the constrained jet is close to a top-hat jet with an extremely small half opening angle of about 0.015 rad,and the circumburst matter density is as small as 10^(-7)cm^(-3),which suggests that this peculiar long GRB might originate from metal-poor stars with low mass-loss rates.To explain the late time optical light curves of GRB 070125,the effects of the lateral expansion and the participation factor of electrons that are accelerated by the shock have to be taken into account.The constrained results for GRB 070125 show that the jet is also close to a top-hat jet with a half opening angle of about 0.1 rad,the viewing angle is about 0.05 rad,the circumburst density is about 10 cm^(-3),and the participation factor is about 0.1.The jet energy of the two bursts is required to be~1051–1052 erg,which can be produced by a millisecond magnetar or a hyper-accreting black hole.
基金Supported by the Natural Science Foundation of China(11773003,11875264,12003007,12173091,U1931201,U2031105)the Fundamental Research Funds for the Central Universities(2020kfyXJJS039)。
文摘Combining observations of multi-messengers help in boosting the sensitivity of astrophysical source searches,and probe various aspects of the source physics.In this chapter we discuss how LHAASO observations of very high energy(VHE)gamma rays in combination with telescopes for the other messengers can help in solving the origins of VHE neutrinos and galactic and extragalactic cosmic rays.
