ALMA Titan wind velocity maps for CH3CN, HC3N and HNC (derived from observations on August 2016 and May 2017)

These FITS files contain wind velocities (in m/s) as a function of angular offset (in RA/dec.) from the center of Titan's disk, derived from ALMA observations of CH3CN, HC3N and HNC in August 2016 and May 2017. We followed the method of Lellouch et al. (2019) to determine radial velocities (along the line of sight) for each gas as a function of spatial coordinate in the ALMA images. This involved extracting individual spectra from the data cubes and fitting the emission lines with Gaussians to determine their Doppler shifts.本批FITS文件（FITS）包含以米每秒（m/s）为单位的风场速度数据，该数据为相对于土卫六（Titan）圆盘中心的角偏移（以赤经/赤纬RA/dec.为单位）的函数，源自2016年8月与2017年5月针对氰化甲烷（CH3CN）、氰乙炔（HC3N）及异氰化氢（HNC）开展的阿塔卡马大型毫米波/亚毫米波阵列（ALMA）观测。我们参照Lellouch等人（2019）提出的方法，根据ALMA影像中的空间坐标，计算各气体组分的视向速度（沿视线方向）。该分析流程包含从数据立方体中提取单条光谱，并利用高斯函数对发射谱线进行拟合，以测定其多普勒频移。