A Sharper View Of Pal 5'S Tails: Discovery Of Stream Perturbations With A Novel Non-Parametric Technique

Here we release some data on the Pal 5 stellar stream from the arXiv:1609.01282 paper. The file pal5_measurements.fits stores the Pal 5 stream measurements , as shown on Figure 5 of the paper, with the following columns phi1 Angle along the stream in degrees ( the coordinate system is defined in the paper) phi2 Angle across the stream in degrees sbstream Central surface brightness of the stream in stars per square arcmin ldens Linear density of the stream in stars/arcmin cumdens Cumulative density of the (leading/trailing) tail from the progenitor width Gaussian sigma of the stream in degrees bgdens density of background stars The columns with _16, _50, _84 appended to their name refer to the 16%, 50% 84% percentiles inferred from the posterior samples. We also provide the MCMC chains that could be used to measure the covariance matrices of different parameters: The chains are stored in the fits file with the columns phi2_i, logI_j, logSig_j, logB0_j, logB1_j referring to the stream track values at the nodes, log of stream surface brightness, log of stream width, log of the background density and log of background density slope (see paper for more details).本工作发布了arXiv:1609.01282论文中涉及Pal 5恒星流（Pal 5 stellar stream）的相关数据集。 文件pal5_measurements.fits存储了本论文图5中展示的Pal 5恒星流观测测量数据，其包含以下列字段： - phi1：沿恒星流方向的角度（单位为度，坐标系定义详见论文） - phi2：垂直于恒星流方向的角度（单位为度） - sbstream：恒星流中心表面亮度，单位为恒星数/平方角分 - ldens：恒星流线密度，单位为恒星数/角分 - cumdens：源自源天体的（前导/尾随）尾的累积密度 - width：恒星流的高斯分布标准差，单位为度 - bgdens：背景恒星数密度 名称后缀为_16、_50、_84的列字段，分别代表基于后验样本推导得到的16%、50%、84%分位数。 本数据集同时提供了可用于估算不同参数协方差矩阵的马尔可夫链蒙特卡洛（Markov Chain Monte Carlo, MCMC）采样链。该采样链存储于fits格式文件中，其列字段包括phi2_i、logI_j、logSig_j、logB0_j、logB1_j，分别对应节点处的恒星流轨迹值、恒星流表面亮度的对数、恒星流宽度的对数、背景恒星数密度的对数以及背景数密度斜率的对数（详细说明参见论文）。