X-ray Hotspots in the Northwest Shell of the Supernova Remnant RX J1713.7$-$3946

Abstract

The supernova remnant (SNR) RX J1713.7$-$3946 is one of the best-studied accelerators of cosmic rays because of its strong nonthermal X-ray and gamma-ray radiation. We have analyzed accumulated \chandra\ observations with a total exposure time of $\sim$266 ks in the northwest rim of RX J1713.7$-$3946. We detect a substantially large number of point-like sources, referred to as ``hotspots'', which are likely associated with the remnant. The spectra of the hotspots are well described by an absorbed power-law model. The spectral properties ($10^{21}\mathrm{c}{\mathrm{m}}^{-2}\lesssim N_H\lesssim 10^{23}\mathrm{c}{\mathrm{m}}^{-2}$ and $0.5\lesssim \Gamma \lesssim 6$) are different from diffuse X-ray emission in RX J1713.7$-$3946, and the harder hotspot tends to have the larger $N_H$. We also confirm yearly and monthly variabilities of flux for some hotspots. We propose that RX J1713.7$-$3946 is embedded in a complex surroundings where some dense molecular clumps and cores exist inside a wind-blown cavity, and that the hotspot traces synchrotron emission caused by an interaction of shock waves of the SNR and dense molecular cores with a number density of $10^5-10^7{\mathrm{cm}}^{-3}$. The X-ray radiation of the hotspot might be emitted from both primary electrons accelerated at the shocks and secondary electrons produced by the interaction of accelerated protons with the cores.

15 pages, 8 figures, 3 tables; Accepted for publication in ApJ

References in corpus (8)

• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• Primary particle acceleration above 100 TeV in the shell-type Supernova Remnant RX J1713.7-3946 with deep H.E.S.S. observations
• Observations of the young supernova remnant RX J1713.7-3946 with the Fermi Large Area Telescope
• Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku
• Hadronic gamma-rays from RX J1713.7-3946?
• Dense core properties in the Infrared Dark cloud G14.225-0.506 revealed by ALMA
• Expansion measurement of Supernova Remnant RX J1713.7-3946
• NuSTAR observations of the supernova remnant RX J1713.7$-$3946

Cited by in corpus (3)

• ALMA CO Observations of the Gamma-Ray Supernova Remnant RX J1713.7-3946: Discovery of Shocked Molecular Cloudlets and Filaments at 0.01 pc scales
• The interstellar medium in young supernova remnants: key to the production of cosmic X-rays and $\gamma$-rays
• Possible Detection of X-Ray Emitting Circumstellar Material in the Synchrotron-Dominated Supernova Remnant RX J 1713.7-3946