Suzaku Observation of the Unidentified Very High Energy Gamma-Ray Source HESS J1702-420
Fujinaga T, Bamba A, Dotani T, Ozaki M, Puehlhofer G, Wagner S, Reimer O, Funk S, Hinton J (2011)
Publication Type: Journal article
Publication year: 2011
Journal
Book Volume: 63
Pages Range: S857-S864
Abstract
A deep X-ray observation of the unidentified very high energy (VHE) gamma-ray source HESS J1702-420, for the first time, was carried out by Suzaku. No bright sources were detected in the XIS field of view (FOV), except for two faint point-like sources. The two sources, however, are considered not to be related to HESS J1702-420, because their fluxes in the 2-10 keV band (similar to 10(-14) erg s(-1) cm(-2)) are similar to 3 orders of magnitude smaller than the VHF gamma-ray flux in the 1-10 TeV band (F-TeV = 3.1 x 10(-11) erg s(-1) cm(-2)). We compared the energy spectrum of diffuse emission, extracted from the entire XIS FOV with those from nearby observations. If we consider the systematic error of background subtraction, no significant diffuse emission was detected with an upper limit of F-X < 2.7 x 10(-12) erg s(-1) cm(-2) in the 2-10 keV band for an assumed power-law spectrum of Gamma = 2.1 and a source size same as that in the VHE band. The upper limit of the X-ray flux is twelve-times as small as the VHE gamma-ray flux. The large flux ratio (F-TeV/F-X) indicates that HESS J1702-420 is another example of a "dark" particle accelerator. If we use a simple one-zone leptonic model, in which VHE gamma-rays are produced through inverse Compton scattering of the cosmic microwave background and interstellar far-infrared emission, and the X-rays via the synchrotron mechanism, an upper limit of the magnetic field (1.7 mu AG) is obtained from the flux ratio. Because the magnetic field is weaker than the typical value in the galactic plane (3-10 mu G), the simple one-zone model may not work for HESS J1702-420 and a significant fraction of the VHE gamma-rays may originate from protons.
Authors with CRIS profile
Involved external institutions
Japan Aerospace eXploration Agency (JAXA)
Japan (JP)
Aoyama-Gakuin-University / 青山学院大学
Japan (JP)
Eberhard Karls Universität Tübingen
Germany (DE)
Ruprecht-Karls-Universität Heidelberg
Germany (DE)
Leopold-Franzens-Universität Innsbruck / University of Innsbruck
Austria (AT)
Stanford National Accelerator Laboratory (SLAC)
United States (USA) (US)
University of Leicester
United Kingdom (GB)
Japan (JP)
Aoyama-Gakuin-University / 青山学院大学
Japan (JP)
Eberhard Karls Universität Tübingen
Germany (DE)
Ruprecht-Karls-Universität Heidelberg
Germany (DE)
Leopold-Franzens-Universität Innsbruck / University of Innsbruck
Austria (AT)
Stanford National Accelerator Laboratory (SLAC)
United States (USA) (US)
University of Leicester
United Kingdom (GB)
How to cite
APA:
Fujinaga, T., Bamba, A., Dotani, T., Ozaki, M., Puehlhofer, G., Wagner, S.,... Hinton, J. (2011). Suzaku Observation of the Unidentified Very High Energy Gamma-Ray Source HESS J1702-420. Publications of the Astronomical Society of Japan, 63, S857-S864. https://doi.org/10.1093/pasj/63.sp3.S857
MLA:
Fujinaga, Takahisa, et al. "Suzaku Observation of the Unidentified Very High Energy Gamma-Ray Source HESS J1702-420." Publications of the Astronomical Society of Japan 63 (2011): S857-S864.
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