Measuring the broad-band X-ray spectrum from 400 eV to 40 keV in the southwest part of the supernova remnant RX J1713.7-3946

作者：Takahashi Tadayuki^*; Tanaka Takaaki; Uchiyama Yasunobu; Hiraga Junko S; Nakazawa Kazuhiro; Watanabe Shin; Bamba Aya; Hughes John P; Katagiri Hideaki; Kataoka Jun; Kokubun Motohide; Koyama Katsuji; Mori Koji; Petre Robert; Takahashi Hiromitsu; Tsuboi Yoko

来源：Publications of the Astronomical Society of Japan, 2008, 60: S131-S140.

• acceleration of particles
• ISM : individual (RX J1713.7-3946)
• ISM : supernova remnants
• X-rays : ISM

We report on results from Suzaku broadband X-ray observations of the southwest part of the galactic supernova remnant (SNR) RX J1713.7-3946 with an energy coverage of 0.4-40keV. The X-ray spectrum, presumably of synchrotron origin, is known to be completely lineless, making this SNR ideally suited for a detailed study of the X-ray spectral shape formed through efficient particle acceleration at high-speed shocks. With a sensitive hard X-ray measurement from the HXD PIN aboard Suzaku, we determined the hard X-ray spectrum in the 12-40 keV range to be described by a power law with photon index of Gamma = 3.2 +/- 0.2, significantly steeper than the soft X-ray index of Gamma = 2.4 +/- 0.05 measured previously with ASCA and other missions. We find that a simple power law fails to describe the full spectral range of 0.4-40 keV, and instead a power-law with an exponential cutoff with a hard index of Gamma = 1.50 +/- 0.09 and a high-energy cutoff of epsilon(c) = 1.2 +/- 0.3 keV formally provides an excellent fit over the full bandpass. If we use the so-called SRCUT model, as an alternative model, it gives a best-fit rolloff energy of epsilon(roll) = 0.95 +/- 0.04 keV. Together with the TeV gamma-ray spectrum, ranging from 0.3 to 100 TeV, recently obtained by HESS observations, our Suzaku observations of RX J1713.7-3946 provide stringent constraints on the highest-energy particles accelerated in a supernova shock.

• 出版日期2008