ASKAP Project AS108 GASKAP-HI Pilot Survey: SMC HI Emission Cube

This collection contains a 3901x3471x220 pixel data cube consisting of ASKAP data of the neutral hydrogen (HI) emission in the SMC feathered with regridded Parkes data. This cube covers a LSRK velocity range of 40.0 km/s to 253.9 km/s at a spectral resolution of 0.98 km/s. The rms noise level in a single spectral channel is 1.1 K at an angular resolution of 30’’ with an individual pixel size of 7''. This rms level translates to a 5-sigma HI column density detection limit of 4.4e19 cm^-2 over a 20 km/s line width. These data were produced with a custom imaging pipeline that utilizes the joint deconvolution capabilities of WSClean, a third party software suite designed specifically for wide-field imaging, to ensure emission that extends across the boundaries of the ASKAP primary beams is accurately recovered. A multi-scale CLEAN algorithm was employed with scales ranging from 0, 4, 8, 16, 32, 64, 128, and 256 pixels. Other data products include a map of the primary beam response across the ASKAP field-of-view and an integrated intensity image computed over the velocity range of 235.4 km/s to 60.5 km/s. Please see PAPER PLACEHOLDER for comprehensive details on the calibration, imaging, and properties of these data.

本数据集包含一个3901×3471×220像素的数据立方体，其由针对小麦哲伦星系（Small Magellanic Cloud，SMC）中性氢（HI）辐射的ASKAP观测数据，与经重网格化处理的帕克斯（Parkes）望远镜观测数据通过羽毛化拼接技术整合而成。该数据立方体的光谱分辨率为0.98 km/s，覆盖运动学局部标准静止系（Local Standard of Rest, Kinematic，LSRK）下40.0 km/s至253.9 km/s的速度范围。在角分辨率为30″、单个像素尺寸为7″的条件下，单个频谱通道的均方根（Root Mean Square, RMS）噪声电平为1.1 K。该均方根噪声电平对应着在20 km/s的谱线宽度下，中性氢（HI）柱密度的5σ探测极限为4.4×10^19 cm^-2。本数据集采用定制化成像流程生成，该流程依托专为大视场成像设计的第三方软件套件WSClean的联合去卷积功能，确保跨越ASKAP主波束边界的辐射能够被准确还原。流程中采用了多尺度CLEAN算法，其尺度参数取值为0、4、8、16、32、64、128及256像素。其余数据产品包括ASKAP视场内的主波束响应图，以及针对235.4 km/s至60.5 km/s速度区间计算得到的积分强度图像。有关本数据集的定标、成像流程与物理属性的完整细节，请参阅占位符文献（PAPER PLACEHOLDER）。