星系团中央区域热气体二维温度结构探测和热力学成分研究
发布时间：2018-08-18 12:34
【摘要】： 在本论文中,利用新一代X射线天文卫星的高空间和高能量分辨能力,我们分析了星系团中央区域气体的二维温度结构特征和热力学成分,从而为解决星系团气体加热机制等重要前沿课题提供了观测约束。同时,进一步定量评估了探测到的二维温度结构以及其对应的气体加热对测量星系团总引力质量轮廓所造成的影响。 (一)使用高质量Chandra观测数据,我们分析了红移为0.1左右的九个星系团中央400h7?11 kpc区域的二维气体温度分布。应用小波变换和傅里叶功率谱方法,我们探测到了尺度为100h?711 kpc左右的显著二维温度结构。这些二维温度结构的气体温度比周围气体温度高约2 ? 3 keV,所对应的能量超出为1058?60 erg。考虑到星系团气体中典型的湍流速度为200 ? 400 km s?1,这些二维温度结构的有效热传导时标约为108 ?109年,比气体冷却时间小一个量级。因此,可以排除非均匀辐射冷却造成这些温度结构的可能性。通过计算由中央AGN爆发所导致的气泡状结构上升时标,我们推测中央AGN反馈加热[1]有可能是形成这些二维温度结构的主要机制。 为了进一步定量估计星系团中央区域的二维温度结构对总引力质量分布的X射线测量造成的偏离,我们分析了一个包含65个X射线亮星系团样本的二维温度分布和总引力质量轮廓。在流体静力学假定下,利用传统角向平均方法得到的星系团中央区域总引力质量轮廓显著偏离于扣除探测到的二维温度结构后的总引力质量轮廓,最大偏离为10?75%。这反映了目前利用X射线方法测量星系团中央区域暗物质分布的精度上限。同时这一工作也为将来精确计算星系团质量轮廓提供了条件。 (二)为了更全面地研究星系团中央区域气体的热力学状态及其成分,我们分析了一个邻近的典型cD星系团A1795的高质量Chandra、XMM-Newton和Suzaku观测数据。我们发现在中央80h?711 kpc区域内主要存在两相星系团气体成分,其低温成分和高温成分的特征温度分别为2.0 ? 2.4 keV和5.0 ? 5.7 keV。同时,我们探测到了一个较弱的0.8 keV成分,对应中央cD星系内气体。通过对比二维辐射量度(emission measure)比值和金属丰度分布,我们发现在半径为50 ? 100h7?11kpc区域内低温成分含有较高的金属丰度。采用cD corona模型[2],我们解释了观测得到的两相气体温度、密度和辐射量度分布。在此模型中,因受到星系团磁场的约束气体低温成分分布于星系团中央区域,且与周围高温成分保持基本绝热。另外,由于此模型预言的加热源尺度和星系团中央射电瓣尺度一致(≈10h7?11kpc),我们推测中央星系AGN反馈能防止低温高密度成分过快冷却,使其保持热力学稳定态.
[Abstract]:In this paper, using the high spatial and high energy resolution of the new generation of X-ray astronomical satellites, we analyze the two-dimensional temperature structure and thermodynamic composition of the gas in the central region of the cluster. Thus, the observation constraints are provided for solving the important frontier problems such as the gas heating mechanism of the cluster of galaxies. At the same time, the effect of the detected two-dimensional temperature structure and the corresponding gas heating on the measurement of the total gravitational mass profile of the cluster is further quantitatively evaluated. (1) using the high quality Chandra data, we analyze the two-dimensional gas temperature distribution in the central 400h7?11 kpc region of nine galaxies with a redshift of about 0.1. Using wavelet transform and Fourier power spectrum method, we have detected a significant two-dimensional temperature structure with a scale of about 100h?711 kpc. The gas temperature of these two dimensional temperature structures is about 2? 3 Kev higher than that of the surrounding gas, and the corresponding energy exceeds 1058 ~ 60 erg. Considering the typical turbulent velocity of 200 ~ 400 km / s ~ (-1) in a cluster gas, the effective heat conduction time scale of these two-dimensional temperature structures is about 108 ~ 109 years, which is an order of magnitude less than the cooling time of the gas. Thus, the possibility of inhomogeneous radiation cooling resulting in these temperature structures can be excluded. By calculating the rising time scales of bubble structures caused by central AGN bursts, we speculate that central AGN feedback heating [1] may be the main mechanism for the formation of these two-dimensional temperature structures. In order to further quantitatively estimate the deviation caused by the two-dimensional temperature structure in the central region of the cluster from the X-ray measurements of the total gravitational mass distribution, We analyze a two-dimensional temperature distribution and total gravitational mass profile for a sample of 65 X-ray bright clusters. On the assumption of hydrostatics, the total gravity mass profile of the central region of the galaxy cluster obtained by the traditional angular averaging method deviates significantly from the total gravity mass profile after subtracting the detected two-dimensional temperature structure, the maximum deviation being 1075. This reflects the present upper limit of the accuracy of X-ray measurement of dark matter distribution in the central region of the cluster. At the same time, this work also provides the condition for the accurate calculation of the mass profile of the cluster in the future. (2) in order to study more fully the thermodynamic state and composition of gases in the central region of the cluster, we have analysed the high quality Chandra-XMM-Newton and Suzaku observations of a nearby typical CD cluster A1795. It is found that there are mainly two-phase cluster gases in the central 80h?711 kpc region. The characteristic temperatures of the low temperature composition and high temperature composition are 2.0? 2.4 keV and 5.0? 5.7 Kev, respectively. At the same time, we have detected a weak 0. 8 keV component corresponding to the gas in the central CD galaxy. By comparing the (emission measure) ratio and the distribution of metal abundance, we find that the low temperature composition in the region with a radius of 50? 100h7?11kpc contains higher metal abundance. Using the CD corona model [2], we explain the observed distributions of temperature, density and radiance of two-phase gas. In this model, the low temperature composition of the gas confined by the magnetic field of the cluster is distributed in the central region of the cluster, and it remains basically adiabatic with the surrounding high temperature composition. In addition, because the scale of heating source predicted by this model is consistent with the scale of central radio lobe of cluster (鈮，
本文编号：2189489
[Abstract]:In this paper, using the high spatial and high energy resolution of the new generation of X-ray astronomical satellites, we analyze the two-dimensional temperature structure and thermodynamic composition of the gas in the central region of the cluster. Thus, the observation constraints are provided for solving the important frontier problems such as the gas heating mechanism of the cluster of galaxies. At the same time, the effect of the detected two-dimensional temperature structure and the corresponding gas heating on the measurement of the total gravitational mass profile of the cluster is further quantitatively evaluated. (1) using the high quality Chandra data, we analyze the two-dimensional gas temperature distribution in the central 400h7?11 kpc region of nine galaxies with a redshift of about 0.1. Using wavelet transform and Fourier power spectrum method, we have detected a significant two-dimensional temperature structure with a scale of about 100h?711 kpc. The gas temperature of these two dimensional temperature structures is about 2? 3 Kev higher than that of the surrounding gas, and the corresponding energy exceeds 1058 ~ 60 erg. Considering the typical turbulent velocity of 200 ~ 400 km / s ~ (-1) in a cluster gas, the effective heat conduction time scale of these two-dimensional temperature structures is about 108 ~ 109 years, which is an order of magnitude less than the cooling time of the gas. Thus, the possibility of inhomogeneous radiation cooling resulting in these temperature structures can be excluded. By calculating the rising time scales of bubble structures caused by central AGN bursts, we speculate that central AGN feedback heating [1] may be the main mechanism for the formation of these two-dimensional temperature structures. In order to further quantitatively estimate the deviation caused by the two-dimensional temperature structure in the central region of the cluster from the X-ray measurements of the total gravitational mass distribution, We analyze a two-dimensional temperature distribution and total gravitational mass profile for a sample of 65 X-ray bright clusters. On the assumption of hydrostatics, the total gravity mass profile of the central region of the galaxy cluster obtained by the traditional angular averaging method deviates significantly from the total gravity mass profile after subtracting the detected two-dimensional temperature structure, the maximum deviation being 1075. This reflects the present upper limit of the accuracy of X-ray measurement of dark matter distribution in the central region of the cluster. At the same time, this work also provides the condition for the accurate calculation of the mass profile of the cluster in the future. (2) in order to study more fully the thermodynamic state and composition of gases in the central region of the cluster, we have analysed the high quality Chandra-XMM-Newton and Suzaku observations of a nearby typical CD cluster A1795. It is found that there are mainly two-phase cluster gases in the central 80h?711 kpc region. The characteristic temperatures of the low temperature composition and high temperature composition are 2.0? 2.4 keV and 5.0? 5.7 Kev, respectively. At the same time, we have detected a weak 0. 8 keV component corresponding to the gas in the central CD galaxy. By comparing the (emission measure) ratio and the distribution of metal abundance, we find that the low temperature composition in the region with a radius of 50? 100h7?11kpc contains higher metal abundance. Using the CD corona model [2], we explain the observed distributions of temperature, density and radiance of two-phase gas. In this model, the low temperature composition of the gas confined by the magnetic field of the cluster is distributed in the central region of the cluster, and it remains basically adiabatic with the surrounding high temperature composition. In addition, because the scale of heating source predicted by this model is consistent with the scale of central radio lobe of cluster (鈮，
本文编号：2189489
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