SUNYAEV–ZEL'DOVICH EFFECT OBSERVATIONS OF THE BULLET CLUSTER (1E 0657−56) WITH APEX-SZ
SUNYAEV–ZEL'DOVICH EFFECT OBSERVATIONS OF THE BULLET CLUSTER (1E 0657−56) WITH APEX-SZ
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DOI：
10.1088/0004-637x/701/1/42
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发表时间：
2008-07
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通讯作者：
N. Halverson;T. Lanting;P. Ade;K. Basu;A. Bender;B. Benson;F. Bertoldi;Hsiao-mei Cho.;G. Chon;J. Clarke;J. Clarke;M. Dobbs;D. Ferrusca;R. Güsten;W. Holzapfel;Attila Kovacs;J. Kennedy;Z. Kermish;R. Kneissl;Adrian T. Lee;Adrian T. Lee;M. Lueker;J. Mehl;K. Menten;D. Muders;M. Nord;M. Nord;F. Pacaud;T. Plagge;C. Reichardt;P. Richards;R. Schaaf;P. Schilke;F. Schuller;D. Schwan;H. Spieler;C. Tucker;A. Weiss;O. Zahn
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作者：
N. Halverson;T. Lanting;P. Ade;K. Basu;A. Bender;B. Benson;F. Bertoldi;Hsiao-mei Cho.;G. Chon;J. Clarke;J. Clarke;M. Dobbs;D. Ferrusca;R. Güsten;W. Holzapfel;Attila Kovacs;J. Kennedy;Z. Kermish;R. Kneissl;Adrian T. Lee;Adrian T. Lee;M. Lueker;J. Mehl;K. Menten;D. Muders;M. Nord;M. Nord;F. Pacaud;T. Plagge;C. Reichardt;P. Richards;R. Schaaf;P. Schilke;F. Schuller;D. Schwan;H. Spieler;C. Tucker;A. Weiss;O. Zahn
我们利用APEX-SZ仪器在150 GHz的分辨率下观测了子弹星系团（1 E 0657−56）中的Sunyaev-Zel'dovich效应（SZE）。主要的结果是在这个巨大的合并星系团中的SZE地图。在源位置的中心1′半径范围内检测到具有23σ显著性的簇。SZE地图有一个大致相似的形态，在现有的X射线地图的这个系统，我们没有发现任何证据的SZE发射的无线电或红外源的显着污染。为了与来自X射线观测的团簇气体模型进行简单的定量比较，我们将我们的数据拟合到等温椭圆β模型，尽管这样的模型对于这个复杂的合并系统是不够的。利用X射线导出的幂律指数先验，β = 1.04+0.16−0.10，我们发现核心半径rc = 142″ ± 18″，轴比为0.889 ± 0.072，中心温度下降为−771 ± 71 μKCMB，包括±5.5%的通量校准不确定度。将APEX-SZ图与钱德拉X射线观测的投影电子表面密度图相结合，我们确定团簇气体的质量加权温度为Tmg = 10.8 ± 0.9 keV，明显低于一些先前报道的X射线光谱温度。在流体静力学平衡的等温集群气体分布的假设下，我们计算的气体质量分数为长球形和扁球形的几何形状，并发现它是一致的与以前的结果从X射线和弱透镜观测。这项工作是APEX-SZ实验的第一个结果，也是第一个报告的科学结果，来自于一个大型的多路复用超导过渡边缘传感器测辐射热计阵列的观测。
We present observations of the Sunyaev–Zel'dovich effect (SZE) in the Bullet cluster (1E 0657−56) using the APEX-SZ instrument at 150 GHz with a resolution of 1′. The main results are maps of the SZE in this massive, merging galaxy cluster. The cluster is detected with 23σ significance within the central 1′ radius of the source position. The SZE map has a broadly similar morphology to that in existing X-ray maps of this system, and we find no evidence for significant contamination of the SZE emission by radio or IR sources. In order to make simple quantitative comparisons with cluster gas models derived from X-ray observations, we fit our data to an isothermal elliptical β model, despite the inadequacy of such a model for this complex merging system. With an X-ray-derived prior on the power-law index, β = 1.04+0.16−0.10, we find a core radius rc = 142″ ± 18″, an axial ratio of 0.889 ± 0.072, and a central temperature decrement of −771 ± 71 μKCMB, including a ±5.5% flux calibration uncertainty. Combining the APEX-SZ map with a map of projected electron surface density from Chandra X-ray observations, we determine the mass-weighted temperature of the cluster gas to be Tmg = 10.8 ± 0.9 keV, significantly lower than some previously reported X-ray spectroscopic temperatures. Under the assumption of an isothermal cluster gas distribution in hydrostatic equilibrium, we compute the gas mass fraction for prolate and oblate spheroidal geometries and find it to be consistent with previous results from X-ray and weak-lensing observations. This work is the first result from the APEX-SZ experiment, and represents the first reported scientific result from observations with a large array of multiplexed superconducting transition-edge sensor bolometers.