Fast radio bursts(FRBs) are bright radio pulses from the sky with millisecond durations and Jansky-level flux densities. Their origins are still largely uncertain. Here we suggest a new model for FRBs. We argue that t...Fast radio bursts(FRBs) are bright radio pulses from the sky with millisecond durations and Jansky-level flux densities. Their origins are still largely uncertain. Here we suggest a new model for FRBs. We argue that the collision of a white dwarf with a black hole can generate a transient accretion disk, from which powerful episodic magnetic blobs will be launched. The collision between two consecutive magnetic blobs can result in a catastrophic magnetic reconnection, which releases a large amount of free magnetic energy and forms a forward shock. The shock propagates through the cold magnetized plasma within the blob in the collision region, radiating through the synchrotron maser mechanism,which is responsible for a non-repeating FRB signal. Our calculations show that the theoretical energetics, radiation frequency, duration timescale and event rate can be very consistent with the observational characteristics of FRBs.展开更多
The variability in multi-pulse gamma-ray bursts(GRBs)may help to reveal the mechanism of underlying processes from the central engine.To investigate whether the self-organized criticality(SOC)phenomena exist in the pr...The variability in multi-pulse gamma-ray bursts(GRBs)may help to reveal the mechanism of underlying processes from the central engine.To investigate whether the self-organized criticality(SOC)phenomena exist in the prompt phase of GRBs,we statistically study the proper ties of GRBs with more than 3 pulses in each burst by fitting the distributions of several observed physical variables with a Markov Chain Monte Carlo approach,including the isotropic energy E_(iso),the duration time T,and the peak count rate P of each pulse.Our sample consists of 454 pulses in 93 GRBs observed by the CGRO/BATSE satellite.The best-fitting values and uncertainties for these power-law indices of the differential frequency distributions are:α_(E)^(d)=1.54±0.09,α_(T)^(d)=1.82_(-0.15)^(+0.14)andα_(P)^(d)=2.09_(-0.19)^(0.18),while the power-law indices in the cumulative frequency distributions are:α_(E)^(c)=1.44_(-0.10)^(+0.08),α_(T)^(c)=1.75_(-0.13)^(0.11)andα_(P)^(c)=1.99_(-0.19)^(+0.16).We find that these distributions are roughly consistent with the physical framework of a Fractal-Diffusive,Self^Organized Criticality(FD-SOC)system with the spatial dimension S=3 and the classical diffusionβ=1.Our results support that the jet responsible for the GRBs should be magnetically dominated and magnetic instabilities(e.g.,kink model,or tearing-model instability)lead the GRB emission region into the SOC state.展开更多
There are some similarities between bursts of repeating fast radio bursts(FRBs)and giant pulses(GPs)of pulsars.To explore possible relations between them,we study the cumulative energy distributions of these two pheno...There are some similarities between bursts of repeating fast radio bursts(FRBs)and giant pulses(GPs)of pulsars.To explore possible relations between them,we study the cumulative energy distributions of these two phenomena using the observations of repeating FRB 121102 and the GPs of Crab pulsar.We find that the power-law slope of GPs(with fuence≥130 Jy.ms)is 2.85±0.10.The energy distribution of FRB 121102 can be well fitted by a smooth broken power-law function.For the bursts of FRB 121102 above the break energy(1.22×10^(37)erg),the best-ftting slope is 2.90^(+0.55)_(-0344),similar to the index of GPs at the same observing frequency(~1.4 GHz).We further discuss the physical origin of the repeating FRB 121102 in the framework of the super GPs model.And we find that the super GPs model involving a millisecond pulsar is workable and favored for explaining FRB 121102 despite that the magnetar burst model is more popular.展开更多
基金jointly supported by the National Natural Science Foundation of China (Grant No. 11473012)the National Basic Research Program of China (973 program, 2014CB845800)+2 种基金the National Postdoctoral Program for Innovative Talents (BX201700115)the China Postdoctoral Science Foundation funded project (2017M620199)the Strategic Priority Research Program of the Chinese Academy of Sciences "Multi-waveband Gravitational Wave Universe" (XDB23040000)
文摘Fast radio bursts(FRBs) are bright radio pulses from the sky with millisecond durations and Jansky-level flux densities. Their origins are still largely uncertain. Here we suggest a new model for FRBs. We argue that the collision of a white dwarf with a black hole can generate a transient accretion disk, from which powerful episodic magnetic blobs will be launched. The collision between two consecutive magnetic blobs can result in a catastrophic magnetic reconnection, which releases a large amount of free magnetic energy and forms a forward shock. The shock propagates through the cold magnetized plasma within the blob in the collision region, radiating through the synchrotron maser mechanism,which is responsible for a non-repeating FRB signal. Our calculations show that the theoretical energetics, radiation frequency, duration timescale and event rate can be very consistent with the observational characteristics of FRBs.
基金supported by the National Key Research and Development Program of China(2022YFA1603200,2022YFA1603201,and 2022SKA0130100)the Science Challenging Project(TZ2018005)+4 种基金the National Natural Science Foundation of China(12135001,11825502,11921006,11725314,12273113,11903019,11833003,and 12041306)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA25050900)the CAS Project for Young Scientists in Basic Research(YSBR-063)the Youth Innovation Promotion Association(2023331)support from the National Natural Science Funds for Distinguished Young Scholars(11825502)。
基金supported by the National Natural Science Foundation of China(Grant Nos.11673068,11725314,U1831122,11703064,11903019,U1938116)the Shanghai Sailing Program(No.17YF1422600)+2 种基金the Youth Innovation Promotion Association(2017366)the Key Research Program of Frontier Sciences(Grant Nos.QYZDB-SSW-SYS005,ZDBS-LY-7014)the Strategic Priority Research Program uMulti-waveband gravitational wave Universe”(Grant No.XDB23000000)of the Chinese Academy of Sciences.
文摘The variability in multi-pulse gamma-ray bursts(GRBs)may help to reveal the mechanism of underlying processes from the central engine.To investigate whether the self-organized criticality(SOC)phenomena exist in the prompt phase of GRBs,we statistically study the proper ties of GRBs with more than 3 pulses in each burst by fitting the distributions of several observed physical variables with a Markov Chain Monte Carlo approach,including the isotropic energy E_(iso),the duration time T,and the peak count rate P of each pulse.Our sample consists of 454 pulses in 93 GRBs observed by the CGRO/BATSE satellite.The best-fitting values and uncertainties for these power-law indices of the differential frequency distributions are:α_(E)^(d)=1.54±0.09,α_(T)^(d)=1.82_(-0.15)^(+0.14)andα_(P)^(d)=2.09_(-0.19)^(0.18),while the power-law indices in the cumulative frequency distributions are:α_(E)^(c)=1.44_(-0.10)^(+0.08),α_(T)^(c)=1.75_(-0.13)^(0.11)andα_(P)^(c)=1.99_(-0.19)^(+0.16).We find that these distributions are roughly consistent with the physical framework of a Fractal-Diffusive,Self^Organized Criticality(FD-SOC)system with the spatial dimension S=3 and the classical diffusionβ=1.Our results support that the jet responsible for the GRBs should be magnetically dominated and magnetic instabilities(e.g.,kink model,or tearing-model instability)lead the GRB emission region into the SOC state.
基金This work was partially supported by the National Natural Science Foundation of China(Grant Nos.11673068,11725314,U1831122,11903019,11533003,and 11703002)the Youth Innovation Promotion Association(2017366)+4 种基金the Key Research Program of Frontier Sciences(Grant Nos.QYZDB-SSW-SYS005 and ZDBS-LY-7014)the Strategic Priority Research Program"Multi-waveband gravita-tional wave universe"(Grant No.XDB23000000)the Chinese Academy of Sciences,the China Post-doctoral Science Foundation(Nos.2018M631242 and 2020M671876)the Fundamental Research Funds for the Central Universitiesthe National Postdoctoral Program for Innovative Talents(Grant No.BX20200164).
文摘There are some similarities between bursts of repeating fast radio bursts(FRBs)and giant pulses(GPs)of pulsars.To explore possible relations between them,we study the cumulative energy distributions of these two phenomena using the observations of repeating FRB 121102 and the GPs of Crab pulsar.We find that the power-law slope of GPs(with fuence≥130 Jy.ms)is 2.85±0.10.The energy distribution of FRB 121102 can be well fitted by a smooth broken power-law function.For the bursts of FRB 121102 above the break energy(1.22×10^(37)erg),the best-ftting slope is 2.90^(+0.55)_(-0344),similar to the index of GPs at the same observing frequency(~1.4 GHz).We further discuss the physical origin of the repeating FRB 121102 in the framework of the super GPs model.And we find that the super GPs model involving a millisecond pulsar is workable and favored for explaining FRB 121102 despite that the magnetar burst model is more popular.
