A BOW SHOCK OF HEATED DUST SURROUNDING GALACTIC CENTER SOURCE IRS 8

摘要

High-resolution images in the H and K bands obtained by the Gemini North Telescope of the peculiar Galactic center source, IRS 8, reveal a central pointlike object enveloped in a remarkable bow shock, whose apex is located 0.2″ to the northeast. The H-K′ color of the bow shock is considerably redder than that of the central star. A United Kingdom Infrared Telescope (UKIRT) K-band spectrum reveals that the combined spectrum of the point source and bow shock is nearly featureless and that no shocked line emission (e.g., from H_2) is physically associated with the bow. We interpret the bow as resulting from the interaction of the envelope or wind of the central star of IRS 8 with the extension of the northern arm of Sgr A West and/or the circumnuclear disk, and its emission as coming from radiatively heated, and possibly shock heated, dust.