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

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


We report on results from Suzaku broadband X-ray observations of the southwest part of the galactic supernova remnant (SNR) RXJ1713.7-3946 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 12-40keV range to be described by a power law with photon index of Γ = 3.2 ± 0.2, significantly steeper than the soft X-ray index of Γ = 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 Γ = 1.50 ± 0.09 and a high-energy cutoff of εc = 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 εroll = 0.95 ± 0.04 keV. Together with the TeV γ-ray spectrum, ranging from 0.3 to 100TeV, 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.

Original languageEnglish
Pages (from-to)S131-S140
JournalPublications of the Astronomical Society of Japan
Issue numberSPEC. ISS. 1
Publication statusPublished - 2008
Externally publishedYes


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

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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