A New Perspective of the Radio Bright Zone at The Galactic Center: Feedback from Nuclear Activities

Abstract

New observations of Sgr A have been carried out with the VLA using the broadband (2 GHz) continuum mode at 5.5 GHz, covering the central 30 pc region of the RBZ at the Galactic center. Using the MS-MFS algorithms in CASA, we have imaged Sgr A with a resolution of 1", achieving an rms 8 $\mu$Jy/beam, and a dynamic range 100,000:1.The radio image is compared with X-ray, CN emission-line and Paschen-$\alpha$ images obtained using Chandra, SMA and HST/NICMOS, respectively. We discuss several prominent radio features. The "Sgr A West Wings" extend 5 pc from the NW and SE tips of the ionized "Mini-spiral" in Sgr A West to positions located 2.9 and 2.4 arc min to the NW and SE of Sgr A*, respectively. The NW wing, along with several other prominent features, including the "NW Streamers", form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 14.4 pc x 7.3 pc, has a known X-ray counterpart. A row of three thermally emitting rings is observed in the NW lobe. A field containing numerous amorphous radio blobs extends for a distance of ~2 arc min beyond the tip of the SE wing; these features coincide with the SE X-ray lobe. Most of the amorphous radio blobs in the NW and SE lobes have Paschen-$\alpha$ counterparts, suggesting that a shock interaction of ambient gas concentrations with a collimated nuclear wind (outflow) that may be driven by radiation force from the central star cluster within the CND. Finally, we remark on a prominent radio feature located within the shell of the Sgr A East SNR. 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.

18 pages, 9 figures, ApJ accepted

References in corpus (12)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Giant Magnetized Outflows from the Centre of the Milky Way
• A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center
• Dynamics of Dusty Radiation Pressure Driven Shells and Clouds: Fast Outflows from Galaxies, Star Clusters, Massive Stars, and AGN
• Dynamics of Ionized Gas at the Galactic Center: VLA Observations of the 3D Velocity Field and Location of the Ionized Streams in Sagittarius A West
• Wild at Heart:-The Particle Astrophysics of the Galactic Centre
• The XMM-Newton view of the central degrees of the Milky Way
• AGN feedback: galactic-scale outflows driven by radiation pressure on dust
• The triggering mechanism and properties of ionized outflows in the nearest obscured quasars
• Is there a Supermassive Black Hole at the Center of the Milky Way?
• Old supernova dust factory revealed at the Galactic center
• Mapping the Outer Edge of the Young Stellar Cluster in the Galactic Center

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