Resolving the Enigmatic Northern Arm Sources in the Central Parsec

Angelle Tanner

UCLA Astronomy

Abstract:

Diffraction limited 2-25 micron 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 micron

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/HeI

emission line stars like those observed within the central parsec.