Discovery of the “Pigtail” Molecular Cloud
A research team of the Department of Physics, Keio University, has discovered a molecular cloud with a peculiar helical structure by observation with the NRO 45m Telescope at Nobeyama Radio Observatory (NAOJ), National Astronomical Observatory of Japan. The team led by Shinji Matsumura, a second year Ph. D. candidate, and Tomoharu Oka, an Associate Professor, named it a "pigtail" molecular cloud from its morphology. The “pigtail” molecular cloud is located in the Galactic center, approximately 30,000 light years away from the solar system. Giant molecular clouds in this region are orbit around the Galactic center along two closed orbits. At the bottom of the pigtail molecular cloud, these two orbits intersect. The research team analyzed multiple molecular spectral lines in detail. The researchers have revealed that the two giant molecular clouds collide with one another at exactly the bottom of the “pigtail” molecular cloud. These findings suggest that the helical structure of the “pigtail” molecular cloud formed when the two molecular clouds with different orbits frictionally collided and the magnetic tube was twisted.