NON-THERMAL X-Rays AND INTERSTELLAR GAS TOWARD THE Γ-Ray SUPERNOVA REMNANT RX J1713.7–3946: EVIDENCE FOR X-Ray ENHANCEMENT AROUND CO AND H I CLUMPS

Abstract

RX J1713.7−3946 is the most remarkable very-high-energy γ-ray supernova remnant which emits synchrotron X-rays without thermal features. We made a comparative study of CO, Hi and X-rays in order to better understand the relationship between the X-rays, and the molecular and atomic gas.The results indicate that the X-rays are enhanced around the CO and Hi clumps on a pc scale but are decreased inside the clumps on a 0.1 pc scale. Magnetohydrodynamic numerical simulations of the shock interaction with molecular and atomic gas indicate that the interaction between the shock waves and the clumps excite turbulence which amplifies the magnetic field around the clumps (Inoue et al. 2012). We suggest that the amplified magnetic field around the CO and Hi clumps enhances the synchrotron X-rays and possibly the acceleration of cosmic-ray electrons.

Hadronic gamma-rays from RX J1713.7−3946?

“…The clumps that survive the stellar wind and remain embedded in the cavity are characterized by a subparsec size, Lc = 0.1 Lc,−1 pc, and a large density, nc 10 3 nc,3 cm −3 (see the simulations by Inoue et al 2012 and the observations by Fukui et al 2012 andSano et al 2013).…”

Interstellar gas and X-rays toward the Young supernova remnant RCW 86; pursuit of the origin of the thermal and non-thermal X-ray

“…Studies of the ISM in SNR environments have improved our understanding of SNR evolution, shock heating/ionization, acceleration of CRs, and high-energy radiation (e.g., Fukui et al 2012;Inoue et al 2012;Yoshiike et al 2013;Sano et al 2013). In RCW 86, however, deep studies of the ISM have not been reported.…”

Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7−3946

“…(1) Hadronic model based on MHD simulations: The shock interaction with dense clouds excites turbulence, which amplifies the magnetic field up to the mG order (Inoue et al 2012;Sano et al 2013Sano et al , 2015. These results may be crucial for our better understanding of the gamma-ray and X-ray images of SNRs.…”

“…Although weak thermal X-ray emission has recently been detected from the SNR interior (Katsuda et al 2015), the X-ray emission is still dominated by synchrotron radiation, which links directly to the existence of high-energy electrons. Radio observations of CO and H I gas have revealed a highly inhomogeneous medium surrounding the SNR, such as clumpy molecular clouds (Fukui et al 2003Fukui 2013;Moriguchi et al 2005;Sano et al 2010Sano et al , 2013Sano et al , 2015. Another radio observation of CS also confirmed the existence of a very dense (>10 5 cm −3 ) ISM core toward the SNR (Maxted et al 2012).…”

“…Synchrotron X-rays are enhanced around the CO and H I clumps on a length scale of a fewparsecs, 141 but are relatively faint inside the clumps on a subparsec scale. In other words, the peaks in X-ray brightness are offset from those of the CO/H I gas distribution (Sano et al 2013). Indeed, there exist many gas clumps whose associated X-ray peaks are located more than 0.05deg away from their centers.…”