A joint spectro-imaging analysis of the XMM-Newton and HESS observations of the supernova remnant RX J1713.7-3946

¹ Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/SAp, CEA-Saclay, 91191 Gif-sur-Yvette, France e-mail: fabio.acero@cea.fr
² CNRS/IN2P3, Centre d'Études Nucléaires de Bordeaux Gradignan, UMR 5797, Gradignan 33175, France
³ Université Bordeaux I, Centre d'Études Nucléaires de Bordeaux Gradignan, UMR 5797, Gradignan 33175, France
⁴ Instituto de Astronomía y Física del Espacio (IAFE), CC 67, Suc. 28, 1428 Buenos Aires, Argentina
⁵ INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, 50125 Firenze, Italy

Received: 19 December 2008
Accepted: 31 May 2009

Abstract

Context. The supernova remnant (SNR) RX J1713.7-3946 (also known as G347.3-0.5) is part of the class of remnants dominated by synchrotron emission in X-rays. It is also one of the few shell-type SNRs observed at TeV energies allowing us to investigate particle acceleration at SNRs shock.

Aims. Our goal is to compare spatial and spectral properties of the remnant in X- and γ-rays to understand the nature of its TeV emission. This requires the study of the remnant on the same spatial scale at both energies. To complement the non-thermal spectrum of the remnant, we attempt to provide a reliable estimate of the radio flux density.

Methods. In radio, we revisited ATCA data and used HI and mid-infrared observations to differentiate between the thermal and the non-thermal emission. In X-rays, we produced a new mosaic of the remnant and degraded the spatial resolution of the X-ray data to the resolution of the HESS instrument to perform spatially resolved spectroscopy at the same spatial scale in X- and γ-rays. Radial profiles were obtained to investigate the extension of the emission at both energies.

Results. We found that part of the radio emission within the SNR contours is thermal in nature. Taking this into account, we provide new lower and upper limits to the integrated synchrotron flux of the remnant at 1.4 GHz, of 22 Jy and 26 Jy, respectively. In X-rays, we obtained the first full coverage of RX J1713.7-3946 with XMM-Newton. The spatial variation in the photon index seen on small scale in X-rays is smeared out at HESS resolution. A non-linear correlation between the X- and γ-ray fluxes of the type is found. If the flux variation is mainly caused by density variation around the remnant then a leptonic model can more easily reproduce the observed X/γ-ray correlation. In some angular sectors, radial profiles indicate that the bulk of the X-ray emission comes more from the inside of the remnant than in γ-rays.