首页> 外文期刊>The Astrophysical journal >IDENTIFICATION OF GALACTIC BULGE SURVEY X-RAY SOURCES WITH TYCHO-2 STARS
【24h】

IDENTIFICATION OF GALACTIC BULGE SURVEY X-RAY SOURCES WITH TYCHO-2 STARS

机译:用TYCHO-2星识别银河凸起调查X射线源。

获取原文
           

摘要

We identify 69 X-ray sources discovered by the Galactic Bulge Survey (GBS) that are coincident with or very close to bright stars in the Tycho-2 catalog. Additionally, two other GBS sources are resolved binary companions to Tycho-2 stars where both components are separately detected in X-rays. Most of these are likely to be real matches, but we identify nine objects with large and significant X-ray-to-optical offsets as either detections of resolved binary companions or chance alignments. We collate known spectral types for these objects, and also examine Two Micron All Sky Survey colors, variability information from the All-Sky Automated Survey, and X-ray hardness ratios for the brightest objects. Nearly a third of the stars are found to be optically variable, divided roughly evenly between irregular variations and periodic modulations. All fall among the softest objects identified by the GBS. The sample forms a very mixed selection, ranging in spectral class from O9 to M3. In some cases, the X-ray emission appears consistent with normal coronal emission from late-type stars, or wind emission from early-types, but the sample also includes one known Algol, one W UMa system, two Be stars, and several X-ray bright objects likely to be coronally active stars or binaries. Surprisingly, a substantial fraction of the spectroscopically classified, non-coincidental sample (12 out of 38 objects) have late B or A type counterparts. Many of these exhibit redder near-IR colors than expected for their spectral type and/or variability, and it is likely that the X-rays originate from a late-type companion star in most or all of these objects.
机译:我们确定了银河膨胀调查(GBS)发现的69条X射线源,它们与Tycho-2目录中的明亮恒星重合或非常接近。此外,另外两个GBS来源是第谷2号星的解析双星伴星,其中两个成分在X射线中分别被检测到。其中大多数可能是真实的匹配,但是我们将9个具有较大且显着的X射线与光学偏移的对象识别为检测出已解决的二元同伴或机会对准。我们整理这些物体的已知光谱类型,并检查“两种微米的全天候测量”颜色,“全天候自动测量”的可变性信息以及最亮物体的X射线硬度比。发现近三分之一的恒星是光学可变的,在不规则变化和周期性调制之间大致均匀地划分。所有这些都属于GBS识别的最柔软的对象。样品形成非常混合的选择,范围从O9到M3。在某些情况下,X射线的发射看上去与晚期型恒星的正常日冕发射或早期型恒星的风发射一致,但样本还包括一个已知的Algol,一个W UMa系统,两个Be星和几个X射线明亮的物体,可能是日冕活跃的恒星或双星。出乎意料的是,在光谱分类的非巧合样本中(38个对象中有12个)有很大一部分具有B型或A型晚期对应物。其中许多显示的近红外颜色比其光谱类型和/或可变性所预期的要红,并且X射线可能来自大多数或所有这些物体中的晚型伴星。

著录项

获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号