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arXiv 0810.5227astro-ph
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PSR B0818-41亚脉冲漂移和偏振特性的研究

Exploring the remarkable subpulse drift and polarization properties of PSR B0818-41

Bhaswati Bhattacharyya, Yashwant Gupta, Janusz Gil

摘要:

PSR B 0818 -41是少数几个显示多个漂移区且具有明确相位关系的示波器之一。在本文中,我们报告的新结果,从多频GMRT观测的脉冲星。由于正交偏振,在轮廓的边缘处观察到显著的线性偏振和去偏振。圆极化在1060 MHz处的脉冲轮廓的中间附近改变符号,但在325和610 MHz处未观察到。观察到偏振角(PA)的显著频率演化。根据平均轮廓的频率演化、功率放大器摆幅和子脉冲漂移的结果,我们提出了两种可能的发射几何构型:α ~11 °,β ~-5.4 °和α ~175.4 °,β ~-6.9 °。这两种几何形状的脉冲星辐射图案的模拟再现了所观察到的漂移图案的功能相当不错。除了在325 MHz观察到显着的子脉冲漂移,我们报告子脉冲漂移在244和610 MHz。我们观察到漂移率的变化,从负到稳定和稳定到负漂移率的过渡,与零的一些连接。虽然P3 m对于所有漂移区都是相同的,但是P2 m和Delta(Phi)值对于内部漂移区和外部漂移区是不同的。来自前部和后部外部区域的峰值发射偏移约9 P1。利用这些信息,我们解决了混叠问题并预测P4~ 10 s,这使其成为已知最快的旋转木马。PSR B 0818 -41的两个环的漂移模式是锁相的。同样的发现是真实的,所有的脉冲星显示漂移在多个环的发射和限制的理论模型的脉冲星发射机制,有利于泛磁层辐射机制。

英文摘要:

PSR B0818-41 is one of the few pulsars which show multiple drift regions having well defined phase relationship. In this paper we report new results from the multifrequency GMRT observations of this pulsar. Significant linear polarization is observed with depolarization at the edge of the profile, due to orthogonal polarization. Circular polarization changes sign near the middle of the pulse profile at 1060 MHz, but not observed at 325 and 610 MHz. Remarkable frequency evolution of polarization angle (PA) is observed. Based on the frequency evolution of average profile, PA swing and results from subpulse drifting, we propose two possible emission geometries, alpha~11 deg, beta~-5.4 deg and alpha~175.4 deg, beta~-6.9 deg. Simulation of the pulsar radiation pattern with both these geometries reproduces the observed features in the drift pattern quite well. In addition to the remarkable subpulse drifting observed at 325 MHz, we report subpulse drifting at 244 and 610 MHz. We observe changes of drift rates, transitions from negative to stationary and stationary to negative drift rates, with some connection with nulls. Though P3m is the same for all the drift regions, P2m and Delta(Phi) values are different for the inner and outer drift regions. The peak emission from the leading and the trailing outer regions are offset by ~ 9 P1. Utilising this information, we solve the aliasing problem and predict P4~ 10 s, which makes it the fastest known carousel. The drift pattern from the two rings are phase locked for PSR B0818-41. The same is found to be true for, all pulsars showing drifting in multiple rings of emission and puts constraints on the theoretical models of pulsar emission mechanism and, favors a pan magnetospeheric radiation mechanism.

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