A detailed X-ray and radio study of the supernova remnant W44
A detailed X-ray and radio study of the supernova remnant W44
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DOI：
10.1093/mnras/265.3.631
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发表时间：
1993-12
影响因子：
4.8
通讯作者：
L. Jones;Alan Smith;L. Angelini
中科院分区：
文献类型：
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作者：
L. Jones;Alan Smith;L. Angelini
我们分析EXOSAT和爱因斯坦天文台的X射线光谱，爱因斯坦的X射线图像和详细的超新星遗迹W 44的VLA射电图。扩散的软X射线发射，这是只观察到从内部的SNR，主要是热起源。壳层中没有软X射线发射可以通过测量的视线吸收来解释，并且提供了一个研究SNR内部而不会被亮壳层发射混淆的机会。用爱因斯坦IPC测量的内部X射线表面亮度的反投影进行推导的密度分布是相对不敏感的假设。发现密度随着半径减小，在中心和0.8的分数半径之间减小3-4倍。内部密度分布与Sedov解预测的膨胀成均匀介质的情况完全不一致，但可以在很大程度上解释为膨胀成多云星际介质，其中大部分质量处于冷密状态。在这种状态下，大小几乎等于0.4到8 pc的冲击和压缩气体云可能是我们的VLA地图上首次揭示的众多明亮的无线电发射节和细丝的原因。可能在SNR内探测到与脉冲星PSR 1853+01有关的射电同步加速器星云。这个星云是不寻常的，因为它的位置是从脉冲星偏移，并在一个方向一致的运动脉冲星远离信噪比中心。
We analyse EXOSAT and Einstein Observatory X-ray spectra, an Einstein X-ray image and a detailed VLA radio map of the supernova remnant W44. The diffuse soft X-ray emission, which is only observed from the interior of the SNR, is shown to be largely of thermal origin. The absence of soft X-ray emission from the shell can be explained by the measured line-of-sight absorption, and provides an opportunity to study the SNR interior without confusion by bright shell emission. A deprojection of the interior X-ray surface brightness measured with the Einstein IPC is performed to derive density profiles which are relatively insensitive to the assumptions made. The density is found to decrease with radius by a factor of 3-4 between the centre and a fractional radius of 0.8. The interior density profiles are completely inconsistent with those predicted by the Sedov solution for expansion into a uniform medium, but can be largely explained in terms of expansion into a cloudy interstellar medium in which most of the mass resides in a cool dense state. Shocked and compressed clouds of gas of size almost-equal-to 0.4 to 8 pc in this state may be responsible for the numerous bright knots and filaments of radio emission revealed for the first time in our VLA map. A radio synchrotron nebula associated with the pulsar PSR 1853+01 may have been detected within the SNR. This proposed nebula is unusual because its position is offset from the pulsar, and in a direction consistent with motion of the pulsar away from the SNR centre.