THE REMARKABLE MID-INFRARED JET OF THE MASSIVE YOUNG STELLAR OBJECT G35.20-0.74

摘要

The young massive stellar object G35.20—0.74 was observed in the mid-infrared using T-ReCS on Gemini South. Previous observations have shown that the near-infrared emission has a fanlike morphology that is consistent with emission from the northern lobe of a bipolar radio jet known to be associated with this source. Mid-infrared observations presented in this Letter show a monopolar jet-like morphology as well, and it is argued that the mid-infrared emission observed is dominated by thermal continuum emission from dust. The mid-infrared emission nearest the central stellar source is believed to be directly heated dust on the walls of the outflow cavity. The hydroxyl, water, and methanol masers associated with G35.20-0.74 are spatially located along these mid-infrared cavity walls. Narrow jet or outflow cavities such as this may also be the locations of the linear distribution of methanol masers that are found in association with massive young stellar objects. The fact that G35.20—0.74 has mid-infrared emission that is dominated by the outflow, rather than disk emission, is a caution to those who consider mid-infrared emission from young stellar objects to come only from circumstellar disks.