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arXiv 1809.02140astro-ph.HE
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银河系中心磁星PSR J1745-2900的脉冲形态

Pulse Morphology of the Galactic Center Magnetar PSR J1745-2900

Aaron B. Pearlman, Walid A. Majid, Thomas A. Prince, Jonathon Kocz, Shinji Horiuchi

摘要:

我们目前的银河系中心磁星,PSR J1745-2900,在2.3和8.4 GHz的NASA深空网络70米天线,DSS-43的观测结果。我们研究了磁星的无线电剖面形状,通量密度,无线电频谱,和单脉冲行为之间的MJD 57233和57621之间的一年。特别是,磁星表现出显着负的平均光谱指数$\langleα\rangle$ = -1.86 $\pm$ 0.02时,8.4 GHz的轮廓是单峰,这是相当大的,当轮廓是双峰。我们对MJD 57479上8.4 GHz的单脉冲进行了分析,发现在大量的旋转过程中会发射巨脉冲和具有多个发射分量的脉冲。由此产生的单脉冲通量密度分布与对数正态分布不相容。的组件的典型脉冲宽度为~1.8毫秒,和连续组件之间的普遍延迟时间为~7.7毫秒。许多单脉冲发射组件显示显着的频率结构超过带宽~100 MHz,我们相信这是第一次观察到这样的行为从无线电磁星。我们报告了一个特征的单脉冲展宽时间尺度为$\langleτ_{d}\rangle$ = 6.9 $\pm$ 0.2 ms,在8.4 GHz。我们发现,脉冲展宽是高度可变的发射组件之间,不能解释由一个薄的散射屏幕在距离$\gtrsim$ 1千秒差距。我们讨论了磁星的发射可能的内在和外在机制,并将我们的结果与其他磁星、高磁场磁星和快速射电暴进行了比较。

英文摘要:

We present results from observations of the Galactic Center magnetar, PSR J1745-2900, at 2.3 and 8.4 GHz with the NASA Deep Space Network 70 m antenna, DSS-43. We study the magnetar's radio profile shape, flux density, radio spectrum, and single pulse behavior over a ~1 year period between MJDs 57233 and 57621. In particular, the magnetar exhibits a significantly negative average spectral index of $\langleα\rangle$ = -1.86 $\pm$ 0.02 when the 8.4 GHz profile is single-peaked, which flattens considerably when the profile is double-peaked. We have carried out an analysis of single pulses at 8.4 GHz on MJD 57479 and find that giant pulses and pulses with multiple emission components are emitted during a significant number of rotations. The resulting single pulse flux density distribution is incompatible with a log-normal distribution. The typical pulse width of the components is ~1.8 ms, and the prevailing delay time between successive components is ~7.7 ms. Many of the single pulse emission components show significant frequency structure over bandwidths of ~100 MHz, which we believe is the first observation of such behavior from a radio magnetar. We report a characteristic single pulse broadening timescale of $\langleτ_{d}\rangle$ = 6.9 $\pm$ 0.2 ms at 8.4 GHz. We find that the pulse broadening is highly variable between emission components and cannot be explained by a thin scattering screen at distances $\gtrsim$ 1 kpc. We discuss possible intrinsic and extrinsic mechanisms for the magnetar's emission and compare our results to other magnetars, high magnetic field pulsars, and fast radio bursts.

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