论文标题
根据z源GX 17+2中几百秒延迟的检测，限制冠状高度和调整速度
Constraining the Coronal Heights and Readjustment Velocities Based on the Detection of a Few Hundred Seconds Delays in the Z Source GX 17+2
论文作者
论文摘要
中子星Z类型的来源提供了一个独特的平台，以了解接近爱丁顿光度的积聚磁盘-corona几何形状的结构。使用RXTE和NUSTAR卫星数据，我们在GX 17+2中进行了互相关函数（CCF）研究，以限制负责硬X射线的电晕的大小。从RXTE数据中，我们发现在水平和正常分支期间，CCFS显示出反相关的硬（16-30 keV）和软（2-5 keV）X射线延迟的订单，几十至一百秒，平均相关系数为0.42 $ \ pm $ 0.11。很少有观察结果显示滞后相关，并且有一次与无线电发射相吻合。我们还使用GX 17+2的Nustar数据报告了113美元$ 51 s的反相关硬X射线延迟。基于RXTE数据，发现软X射线通量正在变化，表明在延迟期间磁盘 - 科罗纳结构的变化。我们使用相对论进动，过渡层和边界层模型来构成电晕的大小。假设延迟是磁盘 - 科罗纳结构的重新调整时间尺度，则电晕的高度估计为$ \ sim $ 17--100公里。假设截短的磁盘的内部区域被电晕占据，我们会约束冠状会调整速度（v $ _ {Corona} $ = $β$ = $β$ v $ _ {disk} $，其中v $ _ {disk} $是disk of disk of $ $β$β$β$β$ = 0.06--06--06--06--06--06--06--0.12。这项研究表明，观察到的延迟主要取决于不同的冠状调整速度。
Neutron star Z type sources provide a unique platform in order to understand the structure of accretion disk-corona geometry emitting close to the Eddington luminosity. Using RXTE and NuSTAR satellite data, we performed cross correlation function (CCF) studies in GX 17+2 in order to constrain the size of corona responsible for hard X-rays. From the RXTE data, we found that during horizontal and normal branches, the CCFs show anti-correlated hard (16 - 30 keV) and soft (2 - 5 keV) X-ray delays of the order of a few tens to hundred seconds with a mean correlation coefficient of 0.42$\pm$0.11. Few observations shows correlated lags and on one occasion coincident with radio emission. We also report an anti-correlated hard X-ray delay of 113$\pm$51 s using the NuSTAR data of GX 17+2. Based on RXTE data, it was found that soft and hard X-ray fluxes are varying indicating the changes in the disk-corona structure during delays. We bridle the size of corona using relativistic precession, transition layer and boundary layer models. Assuming the delays to be readjustment time scale of disk-corona structure, height of the corona was estimated to be $\sim$ 17--100 km. Assuming that inner region of the truncated disk is occupied by the corona, we constrain the coronal readjustment velocities (v$_{corona}$=$β$ v$_{disk}$, where v$_{disk}$ is the radial velocity component of the disk) of the order of $β$=0.06-0.12. This study indicates that the observed delays are primarily dependent on the varying coronal readjustment velocities.
