论文标题
Cassiopeia a的前进和反向冲击动力学
The forward and reverse shock dynamics of Cassiopeia A
论文作者
论文摘要
我们报告了超新星残留cassiopeia a（CAS A）的正向和反冲击区域的适当运动测量，包括向前冲击的减速/加速度测量值。这些测量结果将19年的观测与Chandra X射线观测站结合在一起，使用4.2-6 KEV连续体带，优先针对X射线同步辐射。对于前向冲击，平均膨胀率为$ 0.218 \ pm 0.029 $％yr $^{ - 1} $，对应于$ \ $ \ 5800 $ km/s的速度。适当动作的时间导数表示在东方的下降，最高$ 1.1 \ times 10^{ - 4} $ yr $^{ - 2} $在西部部分。反向冲击在东方向外移动，但在西部，它以$ -0.0225 \ pm 0.0007 $％yr $^{ - 1} $的膨胀速率向中心移动，对应于$ -1884 \ pm 17 $ km/s。在西部，喷射框架中的反向冲击速度为$ \ gtrsim 3000 $ km/s，达到$ \ sim 8000 $ km/s的峰值，解释了那里的X射线同步发射丝。反向冲击的向后运动可以通过一种场景来解释，在这种情况下，向前冲击遇到了部分，密集，风壳，或者是在短暂的狼射线恒星阶段创建的震动最初通过偏斜的腔体传播的场景。两种情况都与前向冲击的局部加速度一致。最后，我们使用X射线连续体和SI XIII K-Line发射带报告了东北喷气机的适当运动。我们发现膨胀率分别为0.21％yr $^{ - 1} $和0.24％yr $^{ - 1} $，对应于7830--9200 km/s的X射线喷射的速度。
We report on proper motion measurements of the forward- and reverse-shock regions of the supernova remnant Cassiopeia A (Cas A), including deceleration/acceleration measurements of the forward shock. The measurements combine 19 years of observations with the Chandra X-ray Observatory, using the 4.2-6 keV continuum band, preferentially targeting X-ray synchrotron radiation. The average expansion rate is $0.218 \pm 0.029$%yr$^{-1}$ for the forward shock, corresponding to a velocity of $\approx 5800$ km/s. The time derivative of the proper motions indicates deceleration in the east, and an acceleration up to $1.1\times 10^{-4}$ yr$^{-2}$ in the western part. The reverse shock moves outward in the East, but in the West it moves toward the center with an expansion rate of $-0.0225\pm 0.0007$ %yr$^{-1}$, corresponding to $-1884\pm 17$ km/s. In the West the reverse shock velocity in the ejecta frame is $\gtrsim 3000$ km/s, peaking at $\sim 8000$ km/s, explaining the presence of X-ray synchrotron emitting filaments there. The backward motion of the reverse shock can be explained by either a scenario in which the forward shock encountered a partial, dense, wind shell, or one in which the shock transgressed initially through a lopsided cavity, created during a brief Wolf-Rayet star phase. Both scenarios are consistent with the local acceleration of the forward shock. Finally we report on the proper motion of the northeastern jet, using both the X-ray continuum band, and the Si XIII K-line emission band. We find expansion rates of respectively 0.21%yr$^{-1}$ and 0.24%yr$^{-1}$, corresponding to velocities at the tip of the X-ray jet of 7830--9200 km/s.
