Improved Measurements of Molecular Cloud Distances Based on Global Search

The principle of the background-eliminated extinction-parallax (BEEP) method is examining extinction difference between on- and off-cloud regions to reveal jump caused by molecular clouds, thereby revealing distance in complex dust environments. BEEP requires high-quality images clouds high-precision stellar parallaxes data, which can be provided Milky Way Imaging Scroll Painting (MWISP) CO survey Gaia DR2 catalog, as well supplementary AV data. In this work, further improved (BEEP-II) measure cloud distances a global search manner. Applying BEEP-II three mapped MWISP survey, we collectively measured 238 for 234 clouds. Compared with previous results, measures efficiently, particularly those large angular size or complicated environments, making it suitable measurements samples.