Based on the undisturbed, finite thickness disk gravitational potential, we carried out 3-D Monte Carlo simulations of normal pulsars. We find that their scale height evolves in a similar way for different velocity di...Based on the undisturbed, finite thickness disk gravitational potential, we carried out 3-D Monte Carlo simulations of normal pulsars. We find that their scale height evolves in a similar way for different velocity dispersions （δv）： it first increases linearly with time, reaches a peak, then gradually decreases, and finally approaches a stable asymptotic value. The initial velocity dispersion has a very large influence on the scale height. The time evolution of the scale height is studied. When the magnetic decay age is used as the time variable, the observed scale height has a similar trend as the simulated results in the linear stage, from which we derive velocity dispersions in the range 70 - 178km s^-1, which are near the statistical result of 90 - 270km s^-1 for 92 pulsars with known transverse velocities. If the characteristic age is used as the time variable, then the observed and theoretical curves roughly agree for t 〉 10^8 yr only if av 〈 25km s^-1.展开更多
One large glitch was detected in PSR B1737-30 using data spanning from MJD 57999 to 58406 obtained with the newly built Shanghai Tian Ma Radio Telescope(TMRT). The glitch took place at the time around MJD 58232.4 when...One large glitch was detected in PSR B1737-30 using data spanning from MJD 57999 to 58406 obtained with the newly built Shanghai Tian Ma Radio Telescope(TMRT). The glitch took place at the time around MJD 58232.4 when the pulsar underwent an increase in the rotation frequency of △v about 1.38 × 10^(-6) Hz, corresponding to a fractional step change of △v/v～ 8.39 × 10^(-7). Post-glitch v gradually decreased to the pre-glitch value. The frequency derivative was observed to undergo a step change of about-9×10^(-16) s^(-2). Since July 1987, there have been 36 glitches already reported in PSR B1737-30 including this one. According to our analysis, the glitch size distribution is well described by a power law with an index of 1.13. The distribution of the interval between two adjacent glitches(waiting time △T) follows a Poisson probability density function. For PSR B1737-30, the interval is prone to be long after a large glitch. However, no correlation is found between glitch size and the interval since the previous glitch.展开更多
基金Supported by the National Natural Science Foundation of China.
文摘Based on the undisturbed, finite thickness disk gravitational potential, we carried out 3-D Monte Carlo simulations of normal pulsars. We find that their scale height evolves in a similar way for different velocity dispersions （δv）： it first increases linearly with time, reaches a peak, then gradually decreases, and finally approaches a stable asymptotic value. The initial velocity dispersion has a very large influence on the scale height. The time evolution of the scale height is studied. When the magnetic decay age is used as the time variable, the observed scale height has a similar trend as the simulated results in the linear stage, from which we derive velocity dispersions in the range 70 - 178km s^-1, which are near the statistical result of 90 - 270km s^-1 for 92 pulsars with known transverse velocities. If the characteristic age is used as the time variable, then the observed and theoretical curves roughly agree for t 〉 10^8 yr only if av 〈 25km s^-1.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. U1631122, 11403073 and 11633007)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB23010200)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX1-YW-18)the National Key R&D Program of China (2018YFA0404602)
文摘One large glitch was detected in PSR B1737-30 using data spanning from MJD 57999 to 58406 obtained with the newly built Shanghai Tian Ma Radio Telescope(TMRT). The glitch took place at the time around MJD 58232.4 when the pulsar underwent an increase in the rotation frequency of △v about 1.38 × 10^(-6) Hz, corresponding to a fractional step change of △v/v～ 8.39 × 10^(-7). Post-glitch v gradually decreased to the pre-glitch value. The frequency derivative was observed to undergo a step change of about-9×10^(-16) s^(-2). Since July 1987, there have been 36 glitches already reported in PSR B1737-30 including this one. According to our analysis, the glitch size distribution is well described by a power law with an index of 1.13. The distribution of the interval between two adjacent glitches(waiting time △T) follows a Poisson probability density function. For PSR B1737-30, the interval is prone to be long after a large glitch. However, no correlation is found between glitch size and the interval since the previous glitch.
