Spatial distribution of NH2D in massive star-forming regions

Abstract

ABSTRACT To understand the relation between NH2D and its physical environment, we mapped ortho-NH2D $1_{11}^s-1_{01}^a$ at 85.9 GHz toward 24 Galactic late-stage massive star-forming regions with Institut de Radioastronomie Millim${\rm \acute{e}}$trique (IRAM) 30-m telescope. Ortho-NH2D $1_{11}^s-1_{01}^a$ was detected in 18 of 24 sources. Comparing with the distribution of H13CN 1-0 as a dense gas tracer and radio recombination line H42α, ortho-NH2D $1_{11}^s-1_{01}^a$ present complex and diverse spatial distribution in these targets. 11 of the 18 targets, present a different distribution between ortho-NH2D $1_{11}^s-1_{01}^a$ and H13CN 1-0, while no significant difference between these two lines can be found in other 7 sources, mainly due to limited spatial resolution and sensitivity. Moreover, with H42α tracing massive young stellar objects, ortho-NH2D $1_{11}^s-1_{01}^a$ seems to show a relatively weak emission near the massive young stellar objects.