Parkes observations for project P1014 semester 2019OCTS_02

The spatial distribution of neutral gas is important for understanding the interstellar medium (ISM) evolution and star formation. However, the distribution of Tiny Scale Atomic Structures (TSAS), especially the extremely small scale structures with spatial scales ranging from a few to hundreds of AU are largely unexplored. The formation and evolution of TSAS are still on an active debate. Multi-epoch observations of HI absorption against pulsars are a tested, practical observational method to probe the TSAS, due to pulsar’s nature on-off state and proper motions of 1 to 100 AU per year. We thus propose two epoch observations, which are separated by about five months, for three bright pulsars for probing structures ranging from 8 to 1900 AU.