The Nature of Nonthermal X-ray Filaments Near the Galactic Center

Abstract

Recent Chandra and XMM-{\it 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 \kms molecular cloud, with its intense 1.2mm 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.

arXiv comment14 pages, 9 figures, in Cospar 2004 session E1.4; editors: Cara Rakowski and Shami Chatterjee; "Young Neutron Stars and Supernova Remnants", publication: Advances in Space Research (in press)

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• Interstellar magnetic fields in the Galactic center region
• A Wide-area VLA Continuum Survey near the Galactic Center at 6 and 20 cm Wavelengths
• A Catalog of Diffuse X-ray-Emitting Features within 20 pc of Sgr A*: Twenty Pulsar Wind Nebulae?
• Widespread Methanol Emission from the Galactic Center
• Turbulent Origin of the Galactic-Center Magnetic Field: Nonthermal Radio Filaments
• Diffuse X-Ray Sky in the Galactic Center
• 3 mm spectral line survey of two lines of sight toward two typical cloud complexes in the Galactic Center
• Near- and mid-infrared observations in the inner tenth of a parsec of the Galactic center -- Detection of proper motion of a filament very close to Sgr~A*
• The Population of the Galactic Center Filaments: Position Angle Distribution Reveal a Degree-scale Collimated Outflow from Sgr A* along the Galactic Plane
• An Imaging and Spectral Study of Ten X-Ray Filaments around the Galactic Center
• The CARMA 3mm Survey of the Inner $0.7^{\circ }\times 0.4^{\circ }$ of the Central Molecular Zone
• Statistical Properties of the Population of the Galactic Center Filaments II: The Spacing Between Filaments
• Nonthermal filaments from the tidal destruction of clouds in the Galactic center
• G0.173-0.42: an X-ray and radio magnetized filament near the galactic center
• Nonthermal Filamentary Radio Features Within 20 pc of the Galactic Center
• Study of diffuse HII regions potentially forming part of the gas streams around Sgr A*