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arXiv 0911.0763astro-ph.CO
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Abell 1835核团内介质湍流速度的XMM-牛顿直接极限

A direct limit on the turbulent velocity of the intracluster medium in the core of Abell 1835 from XMM-Newton

J. S. Sanders, A. C. Fabian, R. K. Smith, J. R. Peterson

摘要:

我们研究了X射线发光星系团A1835的深XMM-牛顿反射光栅光谱仪(RGS)观测。这是我们第一次在星系团中直接限制湍流加宽的发射谱线。这是可能的,因为在星系团中最冷的X射线发射气体,这是负责线,占据了核心内的一个小区域。视线非热速度加宽90%上限的最保守确定值是274公里/秒,这是从30千秒差距半径内的发射谱线测得的。因此,核心中湍流与热能密度之比小于13%,光谱中没有显示低于~3.5 keV的气体的发射谱线。我们研究的气体的数量作为温度的函数,并把140兆太阳/年(90%)的气体辐射冷却低于3.85千电子伏的限制。

英文摘要:

We examine deep XMM-Newton Reflection Grating Spectrometer (RGS) observations of the X-ray luminous galaxy cluster A1835. For the first time in a galaxy cluster we place direct limits on turbulent broadening of the emission lines. This is possible because the coolest X-ray emitting gas in the cluster, which is responsible for the lines, occupies a small region within the core. The most conservative determination of the 90 per cent upper limit on line-of-sight, non-thermal, velocity broadening is 274 km/s, measured from the emission lines originating within 30 kpc radius. The ratio of turbulent to thermal energy density in the core is therefore less than 13 per cent. There are no emission lines in the spectrum showing evidence for gas below ~3.5 keV. We examine the quantity of gas as a function of temperature and place a limit of 140 Msun/yr (90 per cent) for gas cooling radiatively below 3.85 keV.

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