The analysis of Abell 1835 using a deprojection technique
The analysis of Abell 1835 using a deprojection technique
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DOI：
10.1051/0004-6361:20034006
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发表时间：
2004-06
影响因子：
6.5
通讯作者：
Shu-Mei Jia;Shu-Mei Jia;Y. Chen;Fang Lu;Luonan Chen;Luonan Chen;F. Xiang
中科院分区：
文献类型：
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作者：
Shu-Mei Jia;Shu-Mei Jia;Y. Chen;Fang Lu;Luonan Chen;Luonan Chen;F. Xiang
本文给出了用XMM-Newton方法对阿贝尔1835进行详细的解投影分析的结果，如果我们用等温等离子体模型拟合谱，解投影温度分布在7.6 keV附近的外围区域是平坦的，在中心区域下降到1.55 keV，这可能与气体冷却有关。在中心部分，双组分热等离子体模型可以更好地拟合光谱。此外，冷组分（T = 1.8 keV）具有比热组分（T = 8 keV）低得多的金属丰度，这可能是由于具有较低丰度的冷气体的冷却时间较长。此外，人们发现，没有一个主要的等温组件，标准的冷却流模型不能很好地拟合光谱。根据等温模型拟合结果，我们还导出了电子密度ne，并用双β模型拟合了其径向分布。结合双β模型的ne分布和反投影的X射线气体温度分布，得到了星系团的总质量和总投影质量。投影质量低于弱透镜方法。然而，假设集群扩展到更大的半径，如Clowe & Schneider（2002）所发现的，这两个结果在误差条内是一致的。此外，我们计算了引力透镜弧的存在所暗示的半径为153 kpc的投影质量，这大约是光学透镜确定的质量的一半。
We present the results from a detailed deprojection analysis of Abell 1835 as observed by XMM-Newton .I f we fi t the spectra with an isothermal plasma model, the deprojected temperature profile is flat in the outer region around 7.6 keV and decreases to ∼5.6 keV in the center, which may be connected with the gas cooling. In the central part, a two-component thermal plasma model can fit the spectrum significantly better. Moreover, the cool component (T ∼ 1.8 keV) has a much lower metal abundance than the hot component (T ∼ 8 keV), which may be due to the longer cooling time for the cool gas with lower abundance. In addition, it was found that without a main isothermal component, the standard cooling flow model cannot fit the spectrum satisfactorily. From the isothermal model fitting results we also derived the electron density ne, and fitted its radial distribution with a double-β model. The ne profile inferred with the double-β model and the deprojected X-ray gas temperature profile were then combined to derive the total mass and the total projected mass of the cluster. The projected mass is lower than that derived from the weak lensing method. However, assuming that the cluster extends to a larger radius ∼15 � as found by Clowe & Schneider (2002), the two results are consistent within the error bars. Furthermore, we calculated the projected mass within the radius of ∼153 kpc implied by the presence of a gravitational lensing arc, which is about half of the mass determined from the optical lensing.