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arXiv 1311.7553astro-ph.HE
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1A 0535+262的XMM-牛顿静止观测

XMM-Newton observations of 1A 0535+262 in quiescence

Victor Doroshenko, Andrea Santangelo, Rozaliya Doroshenko, Isabel Caballero, Sergej Tsygankov, Richard Rothschild

摘要:

在低吸积率下,磁化中子星的吸积被认为是受到离心力的抑制。然而,几个来源,已知的脉动在静止的光度低于理论极限预测的离心屏障的发病。1A 0535+262就是其中之一。在这里,我们提出了一个~50 ks长的XMM-牛顿观测1A 0535+262在平静的分析结果。在观测时,中子星靠近阿帕斯特龙,并且源已经保持了两个轨道周期的安静。尽管如此,我们还是探测到了~3e-11 erg/cm 2/s的脉冲X射线通量。几个观察到的属性,包括功率谱,仍然类似于观察到的爆发。特别是,我们已经发现,在静态噪声功率谱中检测到的中断的频率遵循与源处于爆发时观察到的通量相同的相关性。这种相关性与磁层边界处吸积盘的截断有关。我们认为,我们的结果,以及其他参数以前在文献中报道,表明在静止的吸积也收益从吸积盘周围的中子星。所提出的方案一致地解释了在1A 0535+262中观察到的回旋线的能量,以及源的定时特性,包括爆发内和爆发之间的自旋频率演化,以及功率谱中的中断频率。

英文摘要:

Accretion onto magnetized neutron stars is expected to be centrifugally inhibited at low accretion rates. Several sources, however, are known to pulsate in quiescence at luminosities below the theoretical limit predicted for the onset of the centrifugal barrier. The source 1A 0535+262 is one of them. Here we present the results of an analysis of a ~50 ks long XMM-Newton observation of 1A 0535+262 in quiescence. At the time of the observation, the neutron star was close to apastron, and the source had remained quiet for two orbital cycles. In spite of this, we detected a pulsed X-ray flux of ~3e-11 erg/cm2/s . Several observed properties, including the power spectrum, remained similar to those observed in the outbursts. Particularly, we have found that the frequency of the break detected in the quiescent noise power spectrum follows the same correlation with flux observed when the source is in outburst. This correlation has been associated with the truncation of the accretion disk at the magnetosphere boundary. We argue that our result, along with other arguments previously reported in the literature, suggests that the accretion in quiescence also proceeds from an accretion disk around the neutron star. The proposed scenario consistently explains the energy of the cyclotron line observed in 1A 0535+262, and the timing properties of the source including the spin frequency evolution within and between the outbursts, and the frequency of the break in power spectrum.

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。

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