High-resolution observations of Cepheus A
High-resolution observations of Cepheus A
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仙王座 A 的高分辨率观测
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
S. Garrington
中科院分区：
文献类型：
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作者：
V. A. Hughes;R. J. Cohen;S. Garrington
利用MERLIN对仙王座A进行了新的高分辨率6厘米观测，并结合了新的3.7厘米VLA观测。角分辨率与后者是200 mas，与MERLIN是60 mas，除了孤立的未解决的来源，其中实现33 mas。在源2、源3中观察到60质量的未分辨物体，特别是在源9中也观察到33质量的未分辨物体。没有证据表明有任何其他像这样小的物体具有任何显著的通量密度，尽管源8当时是静止的。源9的尺寸上限将最低亮度温度设定为4.3 $\times $10$^5$K，并增加了之前关于它是回旋同步加速器源的建议的可信度。源2和源3的致密天体被认为是由恒星的质量外流产生的，可能是B 0- B1型光谱，但这是不确定的。有一个关于分子外流发电厂的讨论。源8和9是高度依赖时间的天体，出现在高密度气体分裂的中心，估计它们的高温为107 ~ 108 K，表明它们可以产生高速风。另一方面，源2（ii）周围的OH脉泽显示出约10 km s${-1}$的向外速度，这是很小的，但更高速度的风可以隧道通过邻近的空间，甚至负责源7的300 km s${-1}$子弹。红外线偏振矢量的正交外推法不足以精确定位红外线辐射源，但据估计，源2（ii）和3（d）（ii）可能
New high resolution 6 cm observations have been made on Cepheus A using MERLIN, and combined with new VLA observations at 3.7 cm. Angular resolution with the latter was 200 mas, and with MERLIN was 60 mas, except for isolated unresolved sources where 33 mas was achieved. Unresolved objects at 60 mas were observed in Sources 2, 3, and in particular 9 which also was not resolved at 33 mas. There is no evidence for any other object as small as this with any significant flux density, although Source 8 was quiescent at the time. The upper limit to the size of Source 9 sets a minimum brightness temperature of 4.3 $\times$ 10$^5$K, and adds credence to a previous suggestion that it is a gyrosynchrotron source. The compact objects of Sources 2 and 3 are thought to be produced by mass outflow from stars, which could be of spectral type B0 - B1, but this is uncertain. There is a discussion regarding the powerhouse for the molecular outflow. Sources 8 and 9, which are the highly time dependent objects, appear at the centre of the disruption of the high density gas, and their estimated high temperature of 10$^7$ - 10$^8$K indicates that they could produce high velocity winds. On the other hand, the OH masers surrounding Source 2(ii) show an outward velocity of about 10 km s${-1}$, which is small, but higher velocity winds could tunnel through adjacent spaces, and even be responsible for the 300 km s${-1}$ bullet of Source 7. An extrapolation of the orthogonals to the IR polarization vectors are not accurate enough to pinpoint the source of the IR radiation, but it is estimated that Sources 2(ii) and 3(d)(ii) could