In the present paper we study the possibility of a simultaneous generation of radio waves and soft $X$-rays by means of the quasi-linear diffusion (QLD) in the anomalous pulsar AXP 4U 0142+61. Considering the magnetosphere composed of the so-called beam component and the plasma component respectively, we argue that the frozen-in condition will inevitably lead to the generation of the unstable cyclotron waves. These waves, via the QLD, will in turn influence the particle distribution function, leading to certain values of the pitch angles, thus to an efficient synchrotron mechanism, producing soft $X$-ray photons. We show that for physically reasonable parameters of magnetospheric plasmas, the QLD can provide generation of radio waves in the following interval $40$ MHz-$111$ MHz connected to soft $X$-rays for the domain $0.3$keV-$1.4$keV.
We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perpl…
Gravitational waves (GWs) emission due to magnetic deformation mechanism is applied for Soft Gamma Repeaters (SGRs) and Anomalous X-Ray Pulsars(AXPs), described as fast-spinning and magnetized white dwarfs (WDs). The emission is caused by the asymmetry around the rotation axis of the star generated by its own intense magnetic field. Thus, for the first time in the literature, it is estimated the GWs counterpart for SGRs/AXPs described as WD pulsars. We find that some SGRs/AXPs can be observed by the space detectors BBO and DECIGO. In particular, 1E 1547.0-5408 and SGR 1806-20 could be detected…
The 2008 October Swift detection of X-ray bursts/outburst from the transient SGR-like AXP 1E 1547.0-5408
我们报告的详细研究,2008年10月爆发的异常X射线脉冲星(AXP)1 E 1547.0-5408发现通过雨燕/爆发警报望远镜(BAT)探测SGR样短X射线爆发在2008年10月3日。雨燕/X射线望远镜(XRT)在BAT触发后不到100秒就开始观测该源,当时通量(在2-10 keV范围内约为6 E-11 erg/cm^2/s)比其静态水平高出50倍以上。斯威夫特每天监测1 E 1547.0-5408的爆发活动,持续了大约三周。这种策略使我们能够找到一个相位相干的解决方案,为源脉冲后的爆发,其中,除了周期和周期导数,需要一个积极的周期二阶导数项(自旋下降增加)。脉冲形状的时间演化是复杂多变的,在雨燕观测窗口内,脉冲分数从20%增加到50%。XRT光谱可以很好地拟合通过一个单一的组件,无论是一个幂律(PL)或黑体(BB)。在爆发的最初阶段,光谱是硬的,PL光子指数约为2(或kT约为1.4 keV),在BAT触发后的一天内变陡至约4(或kT约为0.8 keV),尽管这两个分量可能在第一天的光谱中同时存在。触发后5天进行的INTEGRAL观测提供了18-60 keV波段1 E 1547.0-5408发射的上限约为2 E-11 erg/cm^2/s。
The Broad-band Noise Characteristics of Selected Anomalous X-Ray Pulsars and Soft Gamma-ray Repeaters
本文给出了2-60 keV能区反常X射线脉冲星(AXP)和软γ重复源(SGR)的宽带噪声结构。我们已经分析了罗西X射线定时探测器正比计数器阵列档案光曲线的四个AXP和一个SGR。我们检测到,这些源的持续发射显示在0.005-0.05 Hz的范围内的低频带限噪声变化从2.5%到70%的综合均方根时间的长时间的静止和以下爆发。我们在1 E 2259+586中发现了仅在2002年大爆发后$\sim$ 2年的限带红噪声。除此之外,系统没有显示出宽带噪声。虽然1 E 2259+586中的噪声上升发生在包括旋转毛刺的爆发之后,但其他毛刺AXP显示宽带噪声没有明显变化,因此该噪声似乎与毛刺无关。唯一显示出宽带噪声显著变化的源是1 E 1048.1-5937,其中噪声以每年$\sim$ 3.6%的速率逐渐上升1.95年。对于这个源的宽带噪声的增加是不相关的持续性和脉冲流量的大幅增加,或其两个短SGR样的爆发。这种噪声的上升确实是在一个长脉冲群之后开始的,但是考虑到该事件的稀疏性,以及类似脉冲群未被注意到的可能性,1 E 1048.1-5937中的噪声上升触发因素不像1 E 2259+586那样明确。其他三个源表明,相比之下,持续的低电平带限噪声。
Soft gamma repeaters (SGR) are identified as single neutron stars (NS) inside the Galaxy, or nearby galaxies, with sporadic transient gamma radiation. A total number of discovered SGR, including relative Anomalous X-ray pulsars (AXP), is few tens of objects. Many of them show periodic radiation, connected with NS rotation, with periods 2-12 s. The slow rotation is accompanied by small rate of loss of rotational energy, which is considerably smaller than the observed sporadic gamma ray luminosity, and is many orders less that the luminosity during giant bursts, observed in 4 SGR. Therefore the …
Star quakes and internal phase transitions within anomalous x-ray pulsars (AXPs) and soft $γ$-ray repeaters (SGRs) can produce mini contractions and pulsar glitches. Shocks break out from their surface following such contractions produce thermal x/$γ$-ray bursts. Highly relativistic dipolar $e^+e^-$ bunches launched from the pulsar polar caps emit fast radio bursts (FRBs) of narrowly beamed coherent curvature radiation, visible if they point in the direction of Earth. Although these surface x/$γ$-ray bursts are isotropic and are many orders of magnitude more energetic than the FRBs, they are d…
VLT/NACO near-infrared observations of the transient radio magnetar 1E 1547.0-5408
尽管经过了大约十年的观测,人们对软伽马射线中继器(SGR)和异常X射线脉冲星(AXP)的光学和红外(IR)发射特性以及驱动它们在这些波长发射的物理过程知之甚少。这主要是由于到目前为止所实现的识别数量有限,总共五个,以及从多波段光学/红外测光获得的稀疏光谱覆盖范围。这项工作的目的是寻找一个可能的候选对手,最近发现的瞬态无线电AXP 1 E 1547.0-5408。我们进行了第一次深近红外(NIR)观测(Ks波段)的1 E 1547.0-5408与VLT在三个晚上(7月8日,12日和8月17日),在X射线源重新亮化后,并在随后的衰变报告在2007年6月左右。我们在1 E 1547.0-5408的3sigma射电位置内或附近探测到四个天体。其中最暗的天体(天体1)亮度K = 20.27 +/- 0.05,这将产生1 E 1547.0-5408的未吸收X射线与近红外线通量比FX/FK ~ 800,即平均低于其他磁星得出的值。在7月8日和8月17日的夜晚没有检测到物体1,这只允许我们将其NIR变化的上限设置为Delta Ks ~ 0.2,这阻止了我们搜索与无线电或X射线通量的相关性。我们在射电位置没有检测到其他物体,在我们最深的VLT图像(7月12日)中计算出的极限Ks ~ 21.7(在5sigma)。根据我们的观察,我们不能自信地提出1 E 1547.0-5408的近红外对应物。对物体1进…
We analyse the aperiodic flaring features, also known as shots, observed in Cyg X-1 in the 0.1-80 keV energy band using a 6.39 ks simultaneous observation with AstroSat and NICER. We detect 49 simultaneous shots in the soft and hard X-ray bands with NICER and AstroSat-LAXPC, respectively. We observe the shot profile for the first time in soft X-rays (0.1-3 keV), which shows a spectral peak at $\sim$2 keV. Using time-averaged spectroscopy, we measured the truncation of the inner accretion disk at $6.7\pm0.2$ gravitational radii. The shot-phase resolved spectroscopy allowed us to identify the or…