Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku

TL;DR

This study uses Suzaku observations to analyze the nonthermal X-ray emission from SNR RX J1713.7-3946, revealing a spectral cutoff and supporting efficient particle acceleration near the theoretical Bohm limit, with implications for the origin of gamma-ray emission.

Contribution

First wide-band Suzaku observations of RX J1713.7-3946 reveal a spectral cutoff and support the hadronic origin of gamma rays, advancing understanding of particle acceleration in supernova remnants.

Findings

Detected hard X-rays up to 40 keV with spectral cutoff.

Electron spectrum consistent with theoretical predictions.

X-ray and gamma-ray emissions are strongly correlated.

Abstract

We present results obtained from a series of observations of the supernova remnant RX J1713.7-3946 by the Suzaku satellite. The observations cover about two-thirds of the remnant surface. We successfully detected hard X-rays up to ~ 40 keV from each pointing. The hard X-ray spectra are described by power-law functions with photon indices of ~ 3.0, which are larger than those in the energy region below 10 keV. Connection of the spatially-integrated XIS and HXD spectra clearly reveals a spectral cutoff in the 0.4--40 keV X-ray spectrum. This cutoff is interpreted to correspond to the maximum acceleration energy of electrons emitting synchrotron radiation. The wide-band coverage of Suzaku for the first time allows us to derive the parent electron spectrum in the cutoff region, which shows good agreement with theoretical predictions. The inferred cutoff energy in the spatially-integrated X-ray spectrum indicates that particle acceleration in the remnant is so efficient that it is almost at the theoretical limit, the so-called Bohm limit. Based on the Suzaku data, we present results of multi-wavelength studies from spectral and morphological points of view. The spectral energy distribution favors the hadronic scenario rather than the leptonic scenario. For the morphology studies, we compare the surface brightness maps from the Suzaku XIS and the H.E.S.S. telescope. We confirm the strong correlation between X-ray and TeV gamma-ray emission. In addition to the correlation, we found that in the bright western rim regions the X-ray emission is brighter than expected from the general X-ray to gamma-ray correlation.