论文标题
从2006年到2020年，CAS A中央紧凑型物体的冷却
The cooling of the Central Compact Object in Cas A from 2006 to 2020
论文作者
论文摘要
我们报告了Cassiopeia中心紧凑型物体（CCO）的六个Chandra观测（四个时期）的研究。这种模式最大程度地减少了频谱延伸的仪器效果，例如堆积。数据是在一个时间跨度约14年的时间内拍摄的。如果为这个已知最年轻的CCO假定非磁性碳气氛，则温度变化被约束为$ \ dot {t} = -2900 \ pm 600 $ k yr $^{ - 1} $或$ \ dot {t}氢柱密度。这些值对应于$ -1.5 \ pm $ -1.5 $ 0.3 $％和$ -2.3 \ pm 0.4 $ 0.4 $％的冷却率分别为每10年。我们讨论了过去五年中的冷却速率明显增加，以及在时期之间被推断的吸收氢柱密度的变化。考虑在一起，这些变化可能表明系统效应，例如由ACIS滤波器增加污染的不完美校准引起的。
We report on the study of six Chandra observations (four epochs) of the Central Compact Object (CCO) in the Cassiopeia A supernova remnant with the ACIS instrument in the subarray mode. This mode minimizes spectrum-distorting instrumental effects such as pileup. The data were taken over a time span ~ 14 years. If a non-magnetic carbon atmosphere is assumed for this youngest known CCO, then the temperature change is constrained to be $\dot{T}=-2900\pm 600$ K yr$^{-1}$ or $\dot{T}=-4500\pm 800 $ K yr$^{-1}$ ($1σ$ uncertainties) for constant or varying absorbing hydrogen column density. These values correspond to cooling rates of $-1.5 \pm 0.3$% per 10yr and $-2.3 \pm 0.4$% per 10yr, respectively. We discuss an apparent increase in the cooling rate in the last five years and the variations of the inferred absorbing hydrogen column densities between epochs. Considered together, these changes could indicate systematic effects such as caused by, e.g., an imperfect calibration of the increasing contamination of the ACIS filter.
