Gas emission and dynamics in the infrared dark cloud G31.23+0.05

Abstract

We performed a multiwavelength study towards the infrared dark cloud (IRDC) G31.23+0.05 with new CO observations from Purple Mountain Observatory and archival data (the GLIMPSE, MIPSGAL, HERSCHEL, ATLASGAL, BGPS and NVSS surveys). From these observations, we identified three IRDCs with systemic velocities of (cloud A), (cloud B) and km s (cloud C) in the line of sight towards IRDC G31.23. Analyses of the molecular and dust emission suggest that cloud A is a filamentary structure containing a young stellar object; clouds B and C both include a starless core. Clouds A and B are gravitationally bound and have a chance to form stars. In addition, the velocity information and the position-velocity diagram suggest that clouds A and B are adjacent in space and provide a clue hinting at a possible cloud-cloud collision. Additionally, the distribution of dust temperature shows a temperature bubble. The compact core in cloud A is associated with an UCHII region, an IRAS source, H2O masers, CH3OH masers and OH masers, suggesting that massive star formation is active there. We estimate the age of the HII region to be (0.03–0.09) Myr, indicating that the star inside is young.