arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2501.15902astro-ph.HE
收藏

伽马射线脉冲星模式变化的进动机制

Precession for the mode change in a gamma-ray pulsar

H. Tong, H. H. Wang

AI总结:

该研究提出脉冲星PSR J2021+4026的模式变化可由阻尼进动解释,结合磁层扭矩和外间隙模型,阐明倾角变化导致自转减慢率与伽马射线通量关联,并区分长期与短期调制起源。

摘要:

PSR J2021+4026是一颗伽马射线脉冲星,其自转减慢率和伽马射线通量存在变化。其计时和发射的变化是相关的,例如,较大的自转减慢率对应较低的伽马射线通量。我们表明,PSR J2021+4026中的模式变化可以用进动情景来理解。在进动模型中,倾角因进动而受到调制。同时,摆动角可能随时间衰减。这导致进动的阻尼。结合磁层扭矩模型和外间隙模型,阻尼进动可以解释:(1)当倾角较大时,自转减慢率将较大,并伴随较低的伽马射线通量。(2)由于进动的阻尼,伽马射线通量和自转减慢率的变化幅度小于先前的结果。由于摆动角较小,调制周期正在变短。最后,我们提出脉冲星中存在两类调制。脉冲星中的长期调制可能源于进动。短期调制可能源于磁层。

英文摘要:

PSR J2021+4026 is a gamma-ray pulsar having variations in its spin-down rate and gamma-ray flux. Its variations in timing and emission are correlated, e.g., a larger spin-down rate for a low gamma-ray flux. We show that the mode change in PSR J2021+4026 can be understood in the precession scenario. In the precession model, the inclination angle is modulated due to precession. At the same time, the wobble angle may decay with time. This results in damping of the precession. Combined with magnetospheric torque model and the outer gap model, the damped precession can explain: (1) when the inclination angle is larger, the spin-down rate will be larger, accompanied by a lower gamma-ray flux. (2) The variation amplitude of the gamma-ray flux and spin-down rate is smaller than previous results due to the damping of the precession. The modulation period is becoming shorter due to a smaller wobble angle. In the end, we propose that there are two kinds of modulations in pulsars. Long-term modulations in pulsars may be due to precession. Short-term modulations may be of magnetospheric origin.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑