Australia Telescope Compact Array Radio Continuum 1384 and 2368 Mhz
  Observations of Sagittarius B
  We present images of the Sagittarius (Sgr) B giant molecular cloud at 2368
and 1384 MHz obtained using new, multi-configuration Australia Telescope
Compact Array (ATCA) observations. We have combined these observations with
archival single-dish observations yielding images at resolutions of 47" by 14"
and 27" by 8" at 1384 and 2368 MHz respectively. These observations were
motivated by our theoretical work (Protheroe et al. 2008) indicating the
possibility that synchrotron emission from secondary electrons and positrons
created in hadronic cosmic ray (CR) collisions with the ambient matter of the
Sgr B2 cloud could provide a detectable (and possibly linearly polarized)
non-thermal radio signal. We find that the only detectable non-thermal emission
from the Sgr B region is from a strong source to the south of Sgr B2, which we
label Sgr B2 Southern Complex (SC). We find Sgr B2(SC) integrated flux
densities of 1.2+/-0.2 Jy at 1384 MHz and 0.7+/-0.1 Jy at 2368 MHz for a source
of FWHM size at 1384 MHz of ~54". Despite its non-thermal nature, the
synchrotron emission from this source is unlikely to be dominantly due to
secondary electrons and positrons. We use polarization data to place 5-sigma
upper limits on the level of polarized intensity from the Sgr B2 cloud of 3.5
and 3 mJy/beam at 1384 and 2368 MHz respectively. We also use the angular
distribution of the total intensity of archival 330 MHz VLA and the total
intensity and polarized emission of our new 1384 MHz and 2368 MHz data to
constrain the diffusion coefficient for transport of the parent hadronic CRs
into the dense core of Sgr B2 to be no larger than about 1% of that in the
Galactic disk. Finally, we have also used the data to perform a spectral and
morphological study of the features of the Sgr B cloud and compare and contrast
these to previous studies.
