Discovery of synchronous X-ray and radio moding of PSR B0823+26
Discovery of synchronous X-ray and radio moding of PSR B0823+26
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DOI：
10.1093/mnras/sty2075
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发表时间：
2018-08
影响因子：
4.8
通讯作者：
W. Hermsen;L. Kuiper;R. Basu;J. Hessels;D. Mitra;J. Rankin;B. Stappers;G. Wright;J. Grießmeier;M. Serylak;A. Horneffer;C. Tiburzi;W. Ho
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作者：
W. Hermsen;L. Kuiper;R. Basu;J. Hessels;D. Mitra;J. Rankin;B. Stappers;G. Wright;J. Grießmeier;M. Serylak;A. Horneffer;C. Tiburzi;W. Ho
对PSR B0823+26与欧空局的XMM-牛顿、巨型米波射电望远镜和低频阵列国际站的同步观测表明，X射线/射电在射电明亮(B)模式和射电安静(Q)模式之间进行了同步切换。在B模式下，我们在0.2−的2keV X射线中探测到PSRB0823+26，发现脉冲发射具有宽的正弦脉冲，比射电主脉冲的相位滞后0.208±0.012，高脉冲分数为70−80%。在Q模式期间，X射线中未检测到PSRB0823+26(2σ上限，B模式通量以下的因子∼9)。用磁化的部分电离氢气大气模型可以全局再现总的X射线能谱、脉冲分布和脉冲分数，该模型包括三个发射成分：一个初级小热点(T∼3.6×10^6K，R∼17m)，一个较大的冷却同心环(T∼1.1×10^6K，R∼280m)和一个对极热点(T∼1.1×10^6K，R∼100m)，用于旋转轴与视线方向∼66°的夹角。后者与射线值(84±0.7)°不一致。在长达数小时的B模式间隔内，平均X射线通量的变化系数为±20%，这可能与短射电零点或短持续时间的弱发射的频率和长度的变化有关。比较了PSRB0823+26的相关X射线/射电模式与PSRB0943+10的反相关模式和PSRB1822−09的无X射线模式。我们推测，PSR B0823+26的X射线/射电开关是由于它所经过的星际介质物质的吸积速率的变化所致。
Simultaneous observations of PSR B0823+26 with ESA’s XMM–Newton, the Giant Metrewave Radio Telescope and international stations of the Low Frequency Array revealed synchronous X-ray/radio switching between a radio-bright (B) mode and a radio-quiet (Q) mode. During the B mode we detected PSR B0823+26 in 0.2 − 2 keV X-rays and discovered pulsed emission with a broad sinusoidal pulse, lagging the radio main pulse by 0.208 ± 0.012 in phase, with high pulsed fraction of 70 − 80 per cent. During the Q mode PSR B0823+26 was not detected in X-rays (2σ upper limit a factor ∼9 below the B-mode flux). The total X-ray spectrum, pulse profile and pulsed fraction can globally be reproduced with a magnetized partially ionized hydrogen atmosphere model with three emission components: a primary small hotspot (T ∼ 3.6 × 10^6 K, R ∼17 m), a larger cooler concentric ring (T ∼ 1.1 × 10^6 K, R ∼280 m) and an antipodal hotspot (T ∼ 1.1 × 10^6 K, R ∼100 m), for the angle between the rotation axis and line of sight direction ∼66°. The latter is in conflict with the radio derived value of (84 ± 0.7)°. The average X-ray flux within hours-long B-mode intervals varied by a factor ±20 per cent, possibly correlated with variations in the frequency and lengths of short radio nulls or short durations of weak emission. The correlated X-ray/radio moding of PSR B0823+26 is compared with the anti-correlated moding of PSR B0943+10, and the lack of X-ray moding of PSR B1822−09. We speculate that the X-ray/radio switches of PSR B0823+26 are due to variations in the rate of accretion of material from the interstellar medium through which it is passing.