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Paper: The Age of the Galactic Center Arc Determined by its mm-Wave Spectral Cut-Off
Volume: 186, The Central Parsecs of the Galaxy
Page: 514
Authors: Sofue, Y.; Reich, W.; Reich, P.; Wielebinski, R.
Abstract: High-resolution radio continuum observations at 43 GHz of the Radio Arc near the Galactic Center were made using the Effelsberg 100-m telescope. The straight non-thermal filaments are hardly seen at 43 GHz, while they are clearly seen at 32 GHz and lower frequencies. The spectral index between 32 GHz and 43 GHz of the brightest straight filament is as steep as α = -1,(S~να), indicating a sharp turnover of the spectrum at these frequencies. Assuming a magnetic field strength of about 1 mG, we estimate the life time of cosmic-ray electrons to be about 4000 years. We conclude that the sharpest non-thermal radio filaments are very short-lived structures. On the other hand, the ``sickle" is clearly visible at 43 GHz and has a flat spectrum confirming its thermal characteristics.
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