论文标题
直接检测星系簇中的动力学Sunyaev-Zel'Dovich效应
Direct detection of the kinetic Sunyaev-Zel'dovich effect in galaxy clusters
论文作者
论文摘要
我们报告了在3.5 Sigma显着性水平的星系簇中的动力学Sunyaev-Zel'Dovich（KSZ）效应的直接检测。测量是通过将Planck地图堆叠在217 GHz的位于Wen-Han-Liu（WHL）目录的星系簇位置的217 GHz。为了避免取消正面和负KSZ信号，我们使用了斯隆数字天空调查（SDSS）星系的大规模分布来估算沿视线的星系簇的特殊速度，并将符号纳入了KSZ信号的速度威特堆叠中。使用此技术，我们能够测量3R500以上星系簇周围的KSZ信号。假设是标准的β模型，我们还发现R500内的气体分数为FGA，500 = 0.12 +-0.04，质量为M500〜1E14 MSUN/H。我们将此结果与来自磁性宇宙流体动力学模拟以及其他KSZ和X射线测量值的预测进行了比较，这些测量的气体分数低于相同质量群集的通用BARYON分数。我们的价值在统计学上与测量和模拟的结果以及我们的测量不确定性中的普遍价值一致。
We report the direct detection of the kinetic Sunyaev-Zel'dovich (kSZ) effect in galaxy clusters with a 3.5 sigma significance level. The measurement was performed by stacking the Planck map at 217 GHz at the positions of galaxy clusters from the Wen-Han-Liu (WHL) catalog. To avoid the cancelation of positive and negative kSZ signals, we used the large-scale distribution of the Sloan Digital Sky Survey (SDSS) galaxies to estimate the peculiar velocities of the galaxy clusters along the line of sight and incorporated the sign in the velocity-weighted stacking of the kSZ signals. Using this technique, we were able to measure the kSZ signal around galaxy clusters beyond 3R500. Assuming a standard beta-model, we also found that the gas fraction within R500 is fgas,500 = 0.12 +- 0.04 for the clusters with the mass of M500 ~ 1e14 Msun/h. We compared this result to predictions from the Magneticum cosmological hydrodynamic simulations as well as other kSZ and X-ray measurements, most of which show a lower gas fraction than the universal baryon fraction for the same mass of clusters. Our value is statistically consistent with results from the measurements and simulations and also with the universal value within our measurement uncertainty.
