We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointi...We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointing was 10 min.We discovered a new pulsar,PSR J1845–0306,which has a spin period of 983.6 ms and a dispersion measure of 444.6±2.0 cm^(−3)·pc,in observations of SNR G29.6+0.1.To judge the association between the pulsar and the SNR,further verification is needed.We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3.No pulsars were detected in the observations of the other three SNRs.展开更多
The X-ray pulsar-based navigation is a novel technology for the satellite autonomous navigation. The position and the velocity of the satellite are deterimined by using the pulse phases detected at the satellite and p...The X-ray pulsar-based navigation is a novel technology for the satellite autonomous navigation. The position and the velocity of the satellite are deterimined by using the pulse phases detected at the satellite and predicted by the pulse timing models. With the detected pulse phase, the satellite position with respect to the Earth center can be calculated along the line-of-sight to the pulsar. Using three pulsars, the satellite position in the in- ertial frame can be resolved. The extended Kalman filter （EKF） algorithm is designed to incorporate the range measurements with the satellite dynamics. Simulation verification shows that the proposed algorithm can accu- rately determine the satellite orbit, with the position error less than 100 m. Furthermore, the factors influencing the navigation performance are also discussed.展开更多
Using a new method of multi-frequency of K parameter,we estimate the ratio of altitudes of radio emission region of pulsars at 430 and 1418 MHz.The value of the ratio is 1.34±0.12 and the power law index of altit...Using a new method of multi-frequency of K parameter,we estimate the ratio of altitudes of radio emission region of pulsars at 430 and 1418 MHz.The value of the ratio is 1.34±0.12 and the power law index of altitude-frequency is 0.24±0.08.It is indicated that the lower radio frequencies originate further out and the emission region is radially narrow.展开更多
In this paper, the propagation of x-ray bursts in the magnetoplasma of pulsar magnetosphere is discussed. The electromagnetic interaction between x-ray bursts and magnetoplasma is described as some geometry. The elect...In this paper, the propagation of x-ray bursts in the magnetoplasma of pulsar magnetosphere is discussed. The electromagnetic interaction between x-ray bursts and magnetoplasma is described as some geometry. The electromagnetic effects of surface superstrong magnetic field and dynamic effects of outflowing magnetoplasma of pulsars are treated as an optical metric. The Gordon metric is introduced to represent the gravitational metric and optical metric. So the propagation of x-ray bursts in magnetoplasma of pulsars can be described as x-ray bursts transmitting in an effective space characterized by Gordon metric. The modification of gravitational redshift, attributed to the flowing magnetoplasma of pulsars, is obtained and it is shown that the modification is of redshift and can reach the same magnitude as the gravitational redshift for ordinary pulsars.展开更多
According to the observational limits on the radius and mass,the fastest rotating pulsar(PSR 1937+21)is probably a strange star,or at least some neutron star equations of state should be ruled out,if we suggest that a...According to the observational limits on the radius and mass,the fastest rotating pulsar(PSR 1937+21)is probably a strange star,or at least some neutron star equations of state should be ruled out,if we suggest that a dipole magnetic field is relevant to its radio emission.We presume that the millisecond pulsar is a trange star with much low mass,small radius and weak magnetic moment.展开更多
PACS:99.10.−x,04.30.Db,97.60.Gb,95.85.Sz DOI:10.1088/0256-307X/30/11/119901 One regrettable error appeared in Eq.(21)of our article[Chin.Phys.Lett.30(2013)100402].The cor-rect one of the equation is as follows.
The effects of aberration,retardation and magnetic field sweep back,which are caused directly or indirectly by pulsar’s rapid rotation,are estimated in order to examine their influences on the geometry asymmetry of t...The effects of aberration,retardation and magnetic field sweep back,which are caused directly or indirectly by pulsar’s rapid rotation,are estimated in order to examine their influences on the geometry asymmetry of the mean pulse profile.The geometric asymmetry exhibits different behaviors at different cases.The millisecond pulsars incline to develop mean pulse profiles with asymmetric contrary to the normal pulsars.The pulsar J0437-4715 is analyzed as an example.展开更多
Many electromagnetic phenomena on the surface of a pulsar can be explained successfully by the Arons-Schorlemann model.Yet several related phenomena have not been accounted for.In this study we provide solutions for s...Many electromagnetic phenomena on the surface of a pulsar can be explained successfully by the Arons-Schorlemann model.Yet several related phenomena have not been accounted for.In this study we provide solutions for several hitherto unsolved problems in this model,such as the mechanism for the return currents,the relationships between modes of changing and nulling of pulsars and the source for the observed cosmic ray positrons with energies greater than IGeV.In addition,we propose an explanation for the distribution of pulsar periods.展开更多
Timing analyses of gamma-ray pulsar Geminga were made to check its rotating stability using released energetic gamma-ray experiment(EGRET)data.Phase motions of Geminga were found from EGRET data in 1995.Joint analysis...Timing analyses of gamma-ray pulsar Geminga were made to check its rotating stability using released energetic gamma-ray experiment(EGRET)data.Phase motions of Geminga were found from EGRET data in 1995.Joint analysis of parameters searching and bootstrap testing showed that the parameters are getting worse when including EGRET data in 1995.Combination of these results may indicate that a small glitch of Geminga occurred in 1995.展开更多
The relativistic explanation of,pulsar drift is based on cm extremely sirnplistia model.The collapsing star is treated as composed of a aollecti.on of particles falling radially znuards.A calculatzon incorporating a f...The relativistic explanation of,pulsar drift is based on cm extremely sirnplistia model.The collapsing star is treated as composed of a aollecti.on of particles falling radially znuards.A calculatzon incorporating a finite angular momentum is found to give reasonable drift velocities provided the inztzal pulsar frequency zs sufficiently high.The values required are not unreasonable.展开更多
In usual statistical analyses,because of diversities of proper parameters of pulsars,some interesting features might be smeared.In order to remove these diversities,we use the mean values for all quantities of pulsars...In usual statistical analyses,because of diversities of proper parameters of pulsars,some interesting features might be smeared.In order to remove these diversities,we use the mean values for all quantities of pulsars,instead of values of individual one to do statistical analyses.Logp/p3-logτand LogL-logτhave been plotted.The most interesting feature is that the radio luminosity of pulsar evidently appears to regrow up after its initial dropping.This feature is difficult to understand in usual models.Two tentatlive interpretations have been given.展开更多
A formula is provided to check the correlation of pulsars and supernova remnants,using only observable pulsar parameters.The validity of this formula depends on the assumption that the value of the initial pulsar freq...A formula is provided to check the correlation of pulsars and supernova remnants,using only observable pulsar parameters.The validity of this formula depends on the assumption that the value of the initial pulsar frequency is much greater than the present value.A test for this assumption is suggested.展开更多
Supernova 1987 A is a core collapse supernova in the Large Magellanic Cloud, inside which the product is most likely a neutron star. Despite the most sensitive available detection instruments from radio to γ-ray wave...Supernova 1987 A is a core collapse supernova in the Large Magellanic Cloud, inside which the product is most likely a neutron star. Despite the most sensitive available detection instruments from radio to γ-ray wavebands being exploited in the pass thirty years, there have not yet been any pulse signals detected. By considering the density of the medium plasma in the remnant of 1987 A, we find that the plasma cut-off frequency is approximately7 GHz, a value higher than the conventional observational waveband of radio pulsars. As derived, with the expansion of the supernova remnant, the radio signal will be detected in 2073 A.D. at 3 GHz.展开更多
The aspect of formation and evolution of the recycled pulsar（PSR J0737-3039 A/B） is investigated, taking into account the contributions of accretion rate, radius and spin-evolution diagram（- diagram） in the double...The aspect of formation and evolution of the recycled pulsar（PSR J0737-3039 A/B） is investigated, taking into account the contributions of accretion rate, radius and spin-evolution diagram（- diagram） in the double pulsar system. Accepting the spin-down age as a rough estimate（or often an upper limit） of the true age of the neutron star, we also impose the restrictions on the radius of this system. We calculate the radius of the recycled pulsar PSR J0737-3039 A ranges approximately from 8.14 to 25.74 km, and the composition of its neutron star nuclear matters is discussed in the mass-radius diagram.展开更多
Recent observations by pulsar timing array collaborations have detected a stochastic common-spectrum signal, which may originate from scalar-induced gravitational waves generated by primordial curvature perturbations ...Recent observations by pulsar timing array collaborations have detected a stochastic common-spectrum signal, which may originate from scalar-induced gravitational waves generated by primordial curvature perturbations during inflation.Using the NANOGrav 15-year data set, we explore this hypothesis by constraining the primordial curvature power spectrum and reheating energy scale. We model the primordial power spectrum with a lognormal form and consider reheating with the equation of state parameter w = 1/6. Our Bayesian analysis reveals a narrow peak in the primordial power spectrum(the width of the spectrum △ < 0.05 at the 95% confidence level) and constrains the reheating temperature to be 0.03 GeV<T_(rh)<7.2 Ge V. The best-fit SIGW spectrum shows a characteristic turning point near f ~ 10^(-8.1)Hz, marking the transition from reheating to radiation domination, providing a unique probe of the properties of the early Universe.展开更多
研究基于PI滤波估计加速度漂移的X射线脉冲星敏感器与加表组合导航算法。因长时间惯导误差积累导致发散,X射线脉冲星敏感器不能实时定位,且不能确定速度,提出利用X射线脉冲星敏感器脉冲到达时间(Time of arrival,TOA)作为观测量,与惯导...研究基于PI滤波估计加速度漂移的X射线脉冲星敏感器与加表组合导航算法。因长时间惯导误差积累导致发散,X射线脉冲星敏感器不能实时定位,且不能确定速度,提出利用X射线脉冲星敏感器脉冲到达时间(Time of arrival,TOA)作为观测量,与惯导推算的航天器位置在脉冲星指向上的投影估计位置误差,基于PI滤波估计加速度漂移,修正惯导误差,通过组合导航连续确定位置/速度。仿真表明,基于X射线脉冲星敏感器相位ϕ与加表组合天文导航算法能有效估计加速度漂移,并给出较高精度的位置/速度。展开更多
基金supported by the National SKA Program of China (Grant No. 2020SKA0120200)the National Natural Science Foundation of China (Grant Nos. 12041303, 12273100, 12041304, and 12288102)+5 种基金the National Key R&D Program of China (Grant No. 2022YFC2205201)the West Light Foundation of the Chinese Academy of Sciences (Grant No. WLFC 2021-XBQNXZ-027)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region (Grant No. 2022A03013-4)the Natural Science Foundation of Xinjiiang Uygur Autonomous Region (Grant No. 2022D01D85)the open program of the Key Laboratory of Xinjiang Uygur Autonomous Region (Grant No. 2020D04049)partly supported by the Operation, Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments, budgeted from the Ministry of Finance of China and administrated by the CAS
文摘We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointing was 10 min.We discovered a new pulsar,PSR J1845–0306,which has a spin period of 983.6 ms and a dispersion measure of 444.6±2.0 cm^(−3)·pc,in observations of SNR G29.6+0.1.To judge the association between the pulsar and the SNR,further verification is needed.We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3.No pulsars were detected in the observations of the other three SNRs.
文摘The X-ray pulsar-based navigation is a novel technology for the satellite autonomous navigation. The position and the velocity of the satellite are deterimined by using the pulse phases detected at the satellite and predicted by the pulse timing models. With the detected pulse phase, the satellite position with respect to the Earth center can be calculated along the line-of-sight to the pulsar. Using three pulsars, the satellite position in the in- ertial frame can be resolved. The extended Kalman filter （EKF） algorithm is designed to incorporate the range measurements with the satellite dynamics. Simulation verification shows that the proposed algorithm can accu- rately determine the satellite orbit, with the position error less than 100 m. Furthermore, the factors influencing the navigation performance are also discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.19773001the Astronomy Project of Climbing Program of National Commit tee of Science and Technology of ChinaDoctoral Program Foundation of Higher Education of China.
文摘Using a new method of multi-frequency of K parameter,we estimate the ratio of altitudes of radio emission region of pulsars at 430 and 1418 MHz.The value of the ratio is 1.34±0.12 and the power law index of altitude-frequency is 0.24±0.08.It is indicated that the lower radio frequencies originate further out and the emission region is radially narrow.
基金Project supported by the National Natural Science Foundation of China (Grant No 10573012)the Shanghai Leading Academic Discipline Program, China (Grant No T0104)
文摘In this paper, the propagation of x-ray bursts in the magnetoplasma of pulsar magnetosphere is discussed. The electromagnetic interaction between x-ray bursts and magnetoplasma is described as some geometry. The electromagnetic effects of surface superstrong magnetic field and dynamic effects of outflowing magnetoplasma of pulsars are treated as an optical metric. The Gordon metric is introduced to represent the gravitational metric and optical metric. So the propagation of x-ray bursts in magnetoplasma of pulsars can be described as x-ray bursts transmitting in an effective space characterized by Gordon metric. The modification of gravitational redshift, attributed to the flowing magnetoplasma of pulsars, is obtained and it is shown that the modification is of redshift and can reach the same magnitude as the gravitational redshift for ordinary pulsars.
基金Supported by the National Natural Science Foundation of China under Grant No.19803001the Special Funds for Major State Basic Research Projects of China。
文摘According to the observational limits on the radius and mass,the fastest rotating pulsar(PSR 1937+21)is probably a strange star,or at least some neutron star equations of state should be ruled out,if we suggest that a dipole magnetic field is relevant to its radio emission.We presume that the millisecond pulsar is a trange star with much low mass,small radius and weak magnetic moment.
文摘PACS:99.10.−x,04.30.Db,97.60.Gb,95.85.Sz DOI:10.1088/0256-307X/30/11/119901 One regrettable error appeared in Eq.(21)of our article[Chin.Phys.Lett.30(2013)100402].The cor-rect one of the equation is as follows.
基金Supported by the National Natural Science Foundation of China under Grant No.19773001the Climbing Program from the state Science and Technology Commission of China,and the Doctoral Program Foundation of Higher Education in China.
文摘The effects of aberration,retardation and magnetic field sweep back,which are caused directly or indirectly by pulsar’s rapid rotation,are estimated in order to examine their influences on the geometry asymmetry of the mean pulse profile.The geometric asymmetry exhibits different behaviors at different cases.The millisecond pulsars incline to develop mean pulse profiles with asymmetric contrary to the normal pulsars.The pulsar J0437-4715 is analyzed as an example.
文摘Many electromagnetic phenomena on the surface of a pulsar can be explained successfully by the Arons-Schorlemann model.Yet several related phenomena have not been accounted for.In this study we provide solutions for several hitherto unsolved problems in this model,such as the mechanism for the return currents,the relationships between modes of changing and nulling of pulsars and the source for the observed cosmic ray positrons with energies greater than IGeV.In addition,we propose an explanation for the distribution of pulsar periods.
基金Supported by the National Natural Science Foundation of China under Grant No.19673010。
文摘Timing analyses of gamma-ray pulsar Geminga were made to check its rotating stability using released energetic gamma-ray experiment(EGRET)data.Phase motions of Geminga were found from EGRET data in 1995.Joint analysis of parameters searching and bootstrap testing showed that the parameters are getting worse when including EGRET data in 1995.Combination of these results may indicate that a small glitch of Geminga occurred in 1995.
文摘The relativistic explanation of,pulsar drift is based on cm extremely sirnplistia model.The collapsing star is treated as composed of a aollecti.on of particles falling radially znuards.A calculatzon incorporating a finite angular momentum is found to give reasonable drift velocities provided the inztzal pulsar frequency zs sufficiently high.The values required are not unreasonable.
文摘In usual statistical analyses,because of diversities of proper parameters of pulsars,some interesting features might be smeared.In order to remove these diversities,we use the mean values for all quantities of pulsars,instead of values of individual one to do statistical analyses.Logp/p3-logτand LogL-logτhave been plotted.The most interesting feature is that the radio luminosity of pulsar evidently appears to regrow up after its initial dropping.This feature is difficult to understand in usual models.Two tentatlive interpretations have been given.
文摘A formula is provided to check the correlation of pulsars and supernova remnants,using only observable pulsar parameters.The validity of this formula depends on the assumption that the value of the initial pulsar frequency is much greater than the present value.A test for this assumption is suggested.
基金Supported by the National Basic Research Program of China under Grant No 2015CB857100the National Key Research and Development Program of China under Grant No 2017YFA0402600the National Natural Science Foundation of China under Grant Nos 11173034,11703003 and U1731238
文摘Supernova 1987 A is a core collapse supernova in the Large Magellanic Cloud, inside which the product is most likely a neutron star. Despite the most sensitive available detection instruments from radio to γ-ray wavebands being exploited in the pass thirty years, there have not yet been any pulse signals detected. By considering the density of the medium plasma in the remnant of 1987 A, we find that the plasma cut-off frequency is approximately7 GHz, a value higher than the conventional observational waveband of radio pulsars. As derived, with the expansion of the supernova remnant, the radio signal will be detected in 2073 A.D. at 3 GHz.
基金Supported by the National Program on Key Research and Development Project under Grant No 2016YFA0400801the National Natural Science Foundation of China under Grant Nos 11173034,11673023 and 11364007+2 种基金the Fundamental Research Funds for the Central Universitythe Key Support Disciplines of Theoretical Physics of Guizhou Province Education Bureau under Grant No ZDXK[2015]38the Youth Talents Project of Science and Technology in Education Bureau of Guizhou Province under Grant No KY[2017]204
文摘The aspect of formation and evolution of the recycled pulsar（PSR J0737-3039 A/B） is investigated, taking into account the contributions of accretion rate, radius and spin-evolution diagram（- diagram） in the double pulsar system. Accepting the spin-down age as a rough estimate（or often an upper limit） of the true age of the neutron star, we also impose the restrictions on the radius of this system. We calculate the radius of the recycled pulsar PSR J0737-3039 A ranges approximately from 8.14 to 25.74 km, and the composition of its neutron star nuclear matters is discussed in the mass-radius diagram.
基金supported by the National Natural Science Foundation of China (Grant No. 12305059)supported by the National Natural Science Foundation of China (Grant No. 12305075)+3 种基金supported by the National Natural Science Foundation of China (Grant No. 12403002)the Joint Fund of Henan Province Science and Technology R&D Program (Grant No. 235200810111)the Startup Research Fund of Henan Academy of Sciences (Grant No. 241841224)the Startup Research Fund of Henan Academy of Sciences (Grant No. 241841221)。
文摘Recent observations by pulsar timing array collaborations have detected a stochastic common-spectrum signal, which may originate from scalar-induced gravitational waves generated by primordial curvature perturbations during inflation.Using the NANOGrav 15-year data set, we explore this hypothesis by constraining the primordial curvature power spectrum and reheating energy scale. We model the primordial power spectrum with a lognormal form and consider reheating with the equation of state parameter w = 1/6. Our Bayesian analysis reveals a narrow peak in the primordial power spectrum(the width of the spectrum △ < 0.05 at the 95% confidence level) and constrains the reheating temperature to be 0.03 GeV<T_(rh)<7.2 Ge V. The best-fit SIGW spectrum shows a characteristic turning point near f ~ 10^(-8.1)Hz, marking the transition from reheating to radiation domination, providing a unique probe of the properties of the early Universe.
文摘研究基于PI滤波估计加速度漂移的X射线脉冲星敏感器与加表组合导航算法。因长时间惯导误差积累导致发散,X射线脉冲星敏感器不能实时定位,且不能确定速度,提出利用X射线脉冲星敏感器脉冲到达时间(Time of arrival,TOA)作为观测量,与惯导推算的航天器位置在脉冲星指向上的投影估计位置误差,基于PI滤波估计加速度漂移,修正惯导误差,通过组合导航连续确定位置/速度。仿真表明,基于X射线脉冲星敏感器相位ϕ与加表组合天文导航算法能有效估计加速度漂移,并给出较高精度的位置/速度。
