X-ray observations of NGC 7582 and the Grus Quartet with the Einstein Observatory
X-ray observations of NGC 7582 and the Grus Quartet with the Einstein Observatory
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爱因斯坦天文台对 NGC 7582 和鹤四重奏的 X 射线观测
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
G. Perola
中科院分区：
文献类型：
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作者：
T. Maccacaro;G. Perola
用成像比例计数器进行的观测显示，格拉斯四重星系中的四个星系中有三个是X射线发射体(NGC7552,7582,7590)。最强的是窄发射线星系(NELG)NGC7582，我们也利用监视器正比计数器的数据证实了变星2A2315-428基本上只由这个星系组成。在这个星系的光谱中发现了一个大的光电截止，相应的N/subH/位于5到10×10/sup 22/cm/sup-2/之间。结果表明，该星系的星际介质和窄发射线气体都不太可能是造成截断的主要原因。通过与NGC4151的类比，其中可变截止被归因于宽线发射气体，N/subH/被发现与NGC7582中可以设置的宽线分量强度的上限相一致，因此可能是NELG核中存在极高速度气体的第一个间接证据。需要进行的一项关键测试是截止日期的时间变化性。
Observations with the Imaging Proportional Counter reveal that three of the four galaxies in the Grus Quartet are X-ray emitters (NGC 7552, 7582, 7590). The strongest is the narrow emission line galaxy (NELG) NGC 7582, and we confirm, also using data from the Monitor Proportional Counter, that the variable 2A 2315--428 consists essentially of this galaxy only. In the spectrum of this galaxy evidence is found of a large photoelectric cutoff, with the corresponding N/sub H/ lying between 5 and 10 x 10/sup 22/ cm/sup -2/. It is shown that both the interstellar medium and the narrow emission line gas of this galaxy are unlikely to be the main causes of the cutoff. By analogy with NGC 4151, where the variable cutoff is attributed to the broad line emitting gas, N/sub H/ is found to be compatible with the upper limits that can be placed on the strength of broad line components in NGC 7582 and could therefore represent the first indirect evidence of very high velocity gas in the nuclei of NELGs. A crucial test to be pursued is time variability in the cutoff.