Survey Observation of CH3NH2 and Its Formation Process
Abstract
We present the observational result of a glycine precursor, methylamine (CH3NH2), together with methanol (CH3OH) and methanimine (CH2NH) towards high-mass star-forming regions, NGC6334I, G10.47+0.03, G31.41+0.3, and W51~e1/e2 using ALMA. The molecular abundances toward these sources were derived using the rotational diagram method and compared with our state-of-the-art chemical model. We found that the observed ratio of "CH3NH2/CH3OH" is in between 0.11 and 2.2. We also found that the observed "CH3NH2/CH3OH" ratio agrees well with our chemical model by considering the formation of CH3NH2 on the grain surface via hydrogenation process to HCN. This result clearly shows the importance of hydrogenation processes to form CH3NH2. NGC63343I MM3, where CH3NH2 was not detected in this study and showed "CH3NH2/CH3OH" ratio of less than 0.02, is clearly distinguished from the other cores.