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Recent broad-band 34 and 44 GHz radio continuum observations of the Galacticcenter have revealed 41 massive stars identified with near-IR counterparts, aswell as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtainedin 2011 and 2014 have been used to derive proper motions of eight young starsnear Sgr A*. The accuracy of proper motion estimates based on near-IRobservations by Lu et al. and Paumard et al. have been investigated by usingtheir proper motions to predict the 2014 epoch positions of near-IR stars andcomparing the predicted positions with those of radio counterparts in the 2014radio observations. Predicted positions from Lu et al. show an rms scatter of 6mas relative to the radio positions, while those from Paumard et al. show rmsresiduals of 20 mas, which is mainly due to uncertainties in the IR-basedproper motions. Under the assumption of homogeneous ionized winds, we alsodetermine the mass-loss rates of 11 radio stars, finding rates that are onaverage $\sim$2 times smaller than those determined from model atmospherecalculations and near-IR data. Clumpiness of ionized winds would reduce themass loss rate of WR and O stars by additional factors of 3 and 10,respectively. One important implication of this is a reduction in the expectedmass accretion rate onto Sgr A* from stellar winds by nearly an order ofmagnitude to a value of few$\times10^{-7}$ \msol\ yr$^{-1}$. Finally, wepresent the positions of 318 compact 34.5 GHz radio sources within 30\arcs\ ofSgr A*. At least 45 of these have stellar counterparts in the near-IR $K_s$(2.18 $\mu$m) and $L'$ (3.8$\mu$m) bands.

Compact Radio Sources within 30" of Sgr A*: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A*

Compact Radio Sources within 30" of Sgr A: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A