论文标题
来自专用的XMM-Newton观察的三个发现的伽马cas类似物的发现
Three discoveries of gamma Cas analogs from dedicated XMM-Newton observations of Be stars
论文作者
论文摘要
在过去的几年中，某些是恒星的特殊性 - 它们与异常硬且强烈的X射线排放的关联 - 已显示出超越几例延伸。在本文中，我们通过使用XMM-Newton对18个恒星进行有限的调查来继续搜索新案例。 The targets were selected either on the basis of a previous X-ray detection (Exosat, ROSAT, XMM-slew survey) without spectral information available, or because of the presence of a peculiar spectral variability.在新的观测值中，只有两个目标仍未发现，而另外三个恒星仅显示微弱的X射线。在样本的三分之一中发现了短期和/或长期变化。样品中X射线最亮13星的光谱表征导致发现了三个新的Gamma CAS（HD44458，HD45995，V558LYR），将总数带到25个已知病例，另一个伽马CAS候选者（HD120678），将总数带到了2个。
In the last years, a peculiarity of some Be stars - their association with unusually hard and intense X-ray emission - was shown to extend beyond a mere few cases. In this paper, we continue our search for new cases by performing a limited survey of 18 Be stars using XMM-Newton. The targets were selected either on the basis of a previous X-ray detection (Exosat, ROSAT, XMM-slew survey) without spectral information available, or because of the presence of a peculiar spectral variability. Only two targets remain undetected in the new observations and three other stars only display faint and soft X-rays. Short-term and/or long-term variations were found in one third of the sample. The spectral characterization of the X-ray brightest 13 stars of the sample led to the discovery of three new gamma Cas (HD44458, HD45995, V558Lyr), bringing the total to 25 known cases, and another gamma Cas candidate (HD120678), bringing the total to 2.
