The nature of nonthermal X-ray filaments near the galactic center |
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| Institution: | 1. Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA;2. Department of Physics, Macquarie University, Sydney, NSW 2109, Australia;3. Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095, USA;4. Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA;5. Department of Astronomy, University of Maryland, MD 20742, USA;1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-70, Cambridge, MA 02138, USA;2. Jansky Fellow, National Radio Astronomy Observatory, and Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-70, Cambridge, MA 02138, USA |
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| Abstract: | Recent Chandra and XMM-Newton observations reported evidence of two X-ray filaments G359.88?0.08 (SgrA-E) and G359.54+0.18 (the ripple filament) near the Galactic center. The X-ray emission from these filaments has a nonthermal spectrum and coincides with synchrotron emitting radio sources. Here, we report the detection of a new X-ray feature coincident with a radio filament G359.90?0.06 (SgrA-F) and show more detailed VLA, Chandra and BIMA observations of the radio and X-ray filaments. In particular, we show that radio emission from the nonthermal filaments G359.90?0.06 (SgrA-F) and G359.54+0.18 (the ripple) has a steep spectrum whereas G359.88?0.08 (SgrA-E) has a flat spectrum. The X-ray emission from both these sources could be due to synchrotron radiation. However, given that the 20 km s?1 molecular cloud, with its intense 1.2 mm dust emission, lies in the vicinity of SgrA-F, it is possible that the X-rays could be produced by inverse Compton scattering of far-infrared photons from dust by the relativistic electrons responsible for the radio synchrotron emission. The production of X-ray emission from ICS allows an estimate of the magnetic field strength of 0.08 mG within the nonthermal filament. This should be an important parameter for any models of the Galactic center nonthermal filaments. |
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