Resolving the Enigmatic Northern Arm Sources in the Central Parsec

Tanner1, A., Ghez1, A., Morris1, M., Becklin1, E.

1 UCLA, 8371 Math Sciences, Los Angeles, CA 90095

E-mail contact:

Diffraction limited 2-25 um images obtained with the Keck telescope have spatially resolved the cool Galactic Center sources IRS 1W, 5, 10W, 21 and 2; enigmatic objects that have eluded classification. Their gaussian convolved sizes (1500 AU or 0.2'' in diameter), along with their mid-IR color temperature, favor the hypothesis that they are centrally heated stellar sources rather than externally heated dust clumps. Our 2.2 um Keck/NIRC images of these sources as well as Gemini AO images of IRS 8 reveal asymmetric structures indicative of a bow shock. Most likely, these objects are windy, hot stars which happen to be situated along the path of the infalling Northern Arm and are interacting with the associated gas and dust. The presence of such large bow shocks around these objects suggests that their central heating sources have large winds and mass-loss rates which are expected from Wolf-Rayet or AGB stars like those observed within the central parsec.