New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband ( 2 GHz ) continuum mode at 5.5 GHz .
The field of view covers the central 13′ ( 30 pc ) region of the radio-bright zone at the Galactic center .
Using the multi-scale and multi-frequency-synthesis ( MS-MFS ) algorithms in CASA , we have imaged Sgr A with a resolution of 1″ , achieving an rms noise of 8 \mu Jy beam ^ { -1 } , and a dynamic range of 100,000:1 .
Both previously known and newly identified radio features in this region are revealed , including numerous filamentary sources .
The radio continuum image is compared with Chandra X-ray images , with a CN emission-line image obtained with the SMA and with detailed Paschen- \alpha images obtained with HST/NICMOS .
We discuss several prominent features in the radio image .
The “ Sgr A West Wings ” extend 2′ ( 5 pc ) from the NW and SE tips of the Sgr A West HII region ( the ” Mini-spiral ” ) to positions located 2.9 and 2.4 arc min to the northwest and southeast of Sgr A* , respectively .
The NW wing , along with several other prominent features , including the previously identified “ NW Streamers ” , form an elongated radio lobe ( NW lobe ) , oriented nearly perpendicular to the Galactic plane .
This radio lobe , with a size of 6.3′ \times 3.2′ ( 14.4 pc \times 7.3 pc ) , has a known X-ray counterpart .
In the outer region of the NW lobe , a row of three thermally emitting rings is observed .
A field containing numerous amorphous radio blobs extends for a distance of \sim 2 arc min beyond the tip of the SE wing ; these newly recognized features coincide with the SE X-ray lobe .
Most of the amorphous radio blobs in the NW and SE lobes have Paschen- \alpha counterparts .
We propose that they have been produced by shock interaction of ambient gas concentrations with a collimated nuclear wind or an outflow that originated from within the circumnuclear disk ( CND ) .
We also discuss the possibility that the ionized wind or outflow has been launched by radiation force produced by the central star cluster .
Finally , we remark on the detailed structure of a prominent radio emission feature located within the shell of the Sgr A East supernova remnant .
Because this feature – the “ Sigma Front ” – correlates well in shape and orientation with the nearby edge of the CND , we propose that it is a reflected shock wave resulting from the impact of the Sgr A East blast wave on the CND .