A Wide-area VLA Continuum Survey near the Galactic Center at 6 and 20 cm Wavelengths

C. J. Law(1,2), F. Yusef-Zadeh(2), W. D. Cotton(3)


(1) Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
(2) stronomical Institute ``Anton Pannekoek'', University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
(3) National Radio Astronomy Observatory, Charlottesville, VA 22903, USA

Paper: ApJS, August 2008 , in press

EPrint Server: 0803.1412


Abstract:

We describe the results of a mJy-sensitivity, VLA survey of roughly 1 square degree near the Galactic center at 6 and 20 cm. Catalogs of compact and filamentary structures are given and compared to previous surveys of the region. Eight of the unusual, nonthermal radio filaments are detected in 6 cm polarized emission; three of these are the first such detections, confirming their nonthermal nature. This survey found emission from a filament at (l,b)=(359.1,0.75), or a projected distance from Sgr A* of 200 pc, greatly extending the latitude range observed with such features. There is also new evidence for spatial gradients in the 6/20 cm spectral indices of some filaments and we discuss models for these gradients. In studying compact sources, the combination of spectral index and polarization information allows us to identify pulsar candidates and compact \hii regions in the survey. There is also some evidence that the flux measurements of compact sources may be affected by electron scattering from the interstellar medium in the central few hundred parsecs of the Galaxy.


Preprints available from the authors at caseyjlaw@gmail.com , or the raw TeX (no figures) if you click here.

Back to the gcnews home-page.