  The radio bright zone (RBZ) at the Galactic center has been observed with the
JVLA in the A, B and C array configurations at 5.5 and 9 GHz. With a procedure
for high-dynamic range imaging developed on CASA, we constructed deep images a
resolution up to 0.2", achieving rms noises of a few $\mu$Jy/beam. From the
high-resolution and high-dynamics range images at 5.5 and 9 GHz, a population
of compact radio sources ranging from a few mJy to a few tens $\mu$Jy in flux
density is revealed. The steep-spectrum radio sources in RBZ are likely the
candidates of high-energy objects that are associated with neutron stars and/or
stellar mass black holes at the Galactic center. We report new results of the
Cannonball and Galactic center transient (GCT).
