We report the detection of the two-dimensional structure of the radio source associated with the Galactic Center black hole , Sagittarius A* , obtained from Very Long Baseline Array ( VLBA ) observations at a wavelength of 7mm .
The intrinsic source is modeled as an elliptical Gaussian with major axis size 35.4 \times 12.6 R _ { S } in position angle 95 deg East of North .
This morphology can be interpreted in the context of both jet and accretion disk models for the radio emission .
There is supporting evidence in large angular-scale multi-wavelength observations for both source models for a preferred axis near 95 deg .
We also place a maximum peak-to-peak change of 15 % in the intrinsic major axis size over five different epochs .
Three observations were triggered by detection of near infrared ( NIR ) flares and one was simultaneous with a large X-ray flare detected by NuSTAR .
The absence of simultaneous and quasi-simultaneous flares indicates that not all high energy events produce variability at radio wavelengths .
This supports the conclusion that NIR and X-ray flares are primarily due to electron excitation and not to an enhanced accretion rate onto the black hole .