XMM-Newton survey of two Upper Scorpius regions (Argiroffi+ 2006)
XMM-Newton survey of two Upper Scorpius regions (Argiroffi+ 2006)
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对两个上天蝎座区域的 XMM-Newton 调查（Argiroffi 2006）
DOI：
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发表时间：
2006
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通讯作者：
T. M. I. A. D. Palermo
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作者：
C. Argiroffi;F. Favata;E. Flaccomio;A. Maggio;G. Micela;G. Peres;S. D. D. S. F. E. Astronomiche;U. Palermo;Italy.;Astrophysics Division ;Science Support Department of Esa;Noordwijk;T. M. I. A. D. Palermo
目标。我们通过分析XMM-牛顿对年龄为5Myr的天蝎座上星团的两个区域的深入观测，研究了年轻恒星的X射线辐射。方法：研究方法。基于近红外和光学测光，我们在224个探测到的X射线源中确定了22个天蝎座光度成员。我们通过X射线光谱和时序分析得出了天蝎座上恒星的日冕特性。通过对四个强而孤立的恒星耀斑的研究，我们可以得出耀斑环路的长度。结果。在22颗上天蝎星中，有13颗是首次被确认为上天蝎星的光度学成员。该样本包括7颗弱线TTauri星和1颗经典TTauri星，其余来源的性质尚不清楚。除了中等质量恒星HD 142578外，所有探测到的USCO源都是光谱类型从G到晚M的低质量恒星。最强的天蝎座上部源的X射线发射光谱表明，金属贫化等离子体的温度为∼10MK，类似于活跃的主序星的典型日冕发射。该协会中至少59%的探测成员具有可变的X射线发射，并且耀斑的日冕结构似乎比上天蝎座年龄时已经存在的恒星半径短或相当。我们还发现了强烈耀斑期间等离子体金属丰度增加(高达20倍)的迹象。我们在探测到的2 2 4个X射线源中发现了一个新的星系团：其团内介质的X射线光谱显示∼红移为0.4 1±0.0 2。
Aims. We studied X-ray emission from young stars by analyzing the deep XMM-Newton observations of two regions of the Upper Scorpius association with an age of 5 Myr. Methods. Based on near infrared and optical photometry we identified 22 Upper Scorpius photometric members among the 224 detected X-ray sources. We derived coronal properties of Upper Scorpius stars by performing X-ray spectral and timing analyses. The study of four strong and isolated stellar flares allowed us to derive the length of the flaring loops. Results. Among the 22 Upper Scorpius stars, 13 were identified as Upper Scorpius photometric members for the first time. The sample includes 7 weak-line T Tauri stars and 1 classical T Tauri star, while the nature of the remaining sources is unknown. Except for the intermediate mass star HD 142578, all the detected USco sources are low-mass stars of spectral types ranging from G to late M. The X-ray emission spectrum of the most intense Upper Scorpius sources indicates metal depleted plasma with temperature of ∼10 MK, resembling the typical coronal emission of active main sequence stars. At least 59% of the detected members of the association have variable X-ray emission, and the flaring coronal structures appear shorter than or comparable to the stellar radii already at the Upper Scorpius age. We also found indications of increasing plasma metallicity (up to a factor 20) during strong flares. We identified a new galaxy cluster among the 224 X-ray source detected: the X-ray spectrum of its intra cluster medium indicates a redshift of ∼0.41 ± 0.02.