We present a wide-field, subarcminute-resolution VLA image of the Galactic center region at 330 MHz. With a resolution of $7 00 ; 12 00 and an rms noise of 1.6 mJy beam À1 , this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity has more than tripled the census of small-diameter sources in the region, has resulted in the detection of two new nonthermal filaments (NTFs), 18 NTF candidates, and 30 pulsar candidates, reveals previously known extended sources in greater detail, and has resulted in the first detection of Sagittarius A* in this frequency range.

New low-frequency 74 and 330 MHz observations of the Galactic center (GC) region reveal the presence of a large-scale ( ) diffuse source of nonthermal synchrotron emission. A minimum-energy analysis of this emission 6Њ # 2Њ yields a total energy of ∼ ergs and a magnetic field strength of ∼ mG (where f is the 4/7 3/7 52 2/7 (f f ) # 10 6(f/f ) proton to electron energy ratio and f is the filling factor of the synchrotron emitting gas). The equipartition particle energy density is eV cm Ϫ3 , a value consistent with cosmic-ray data. However, the derived magnetic field 2/71.2(f/f ) is several orders of magnitude below the 1 mG field commonly invoked for the GC. With this field the source can be maintained with the supernova rate inferred from the GC star formation. Furthermore, a strong magnetic field implies an abnormally low GC cosmic-ray energy density. We conclude that the mean magnetic field in the GC region must be weak, of order 10 mG (at least on size scales տ125Љ).

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New high-resolution, wide-field 90 cm VLA 1 observations of the Galactic center (GC) region by Nord and coworkers have revealed 20 nonthermal filament ( NTF) candidates. We report 6 cm polarization observations of six of these. All of the candidates have the expected NTF morphology, and two show extended polarization, confirming their identification as NTFs. One of the new NTFs appears to be part of a system of NTFs located in the Sgr B region, 64 pc in projection north of Sgr A. These filaments cross the Galactic plane with an orientation similar to the filaments in the Galactic center radio arc. They extend the scale over which the NTF phenomena is known to occur to almost 300 pc along the Galactic plane. Another NTF was found in the Galactic plane south of the Sgr C filament but with an orientation of 45 to the Galactic plane. This is only the second of 12 confirmed NTFs that is not oriented perpendicular to the Galactic plane. An additional candidate in the Sgr C region was resolved into multiple filamentary structures. Polarization was detected only at the brightness peak of one of the filaments. Several of these filaments run parallel to the Galactic plane and can be considered additional evidence for nonpoloidal magnetic fields at the GC. Together the 90 and 6 cm observations indicate that the GC magnetic field may be more complex than a simple globally ordered dipolar field.