# NuSTAR observations of the supernova remnant RX J1713.7$-$3946

## TL;DR

This study uses NuSTAR X-ray observations to analyze the supernova remnant RX J1713.7$-$3946, revealing detailed spectral and spatial properties of high-energy emissions and electron acceleration mechanisms.

## Contribution

First spatially resolved detection of RX J1713.7$-$3946 up to 20 keV, providing insights into electron acceleration and synchrotron radiation in the remnant.

## Key findings

- X-ray emission detected up to 20 keV for the first time.
- Spectral analysis shows a power-law with exponential cutoff, indicating electron acceleration near the Bohm limit.
- Variation in cutoff energy suggests different acceleration regimes within the remnant.

## Abstract

The shock waves of supernova remnants (SNRs) are prominent candidates for the acceleration of the Galactic cosmic rays. SNR RX J1713.7$-$3946 is one well-studied particle accelerator in our Galaxy because of its strong non-thermal X-ray and gamma-ray radiation. We have performed NuSTAR (3-79 keV) observations of the northwest rim of RX J1713.7$-$3946, where is the brightest part in X-ray and the shock speed is about 4000 km s$^{-1}$. The spatially resolved X-ray emission from RX J1713.7$-$3946 is detected up to 20 keV for the first time. The hard X-ray image in 10-20 keV is broadly similar to the soft-band image in 3-10 keV. The typical spectrum is described by power-law model with exponential cutoff with the photon index $\Gamma$=2.15 and the cutoff energy $\varepsilon_c$=18.8 keV. Using a synchrotron radiation model from accelerated electrons in the loss-limited case, the cutoff energy parameter ranges 0.6-1.9 keV, varying from region to region. Combined with the previous measurement of the shock speed, the acceleration of electrons is close to the Bohm-limit regime in the outer edge, while the standard picture of accelerated particles limited by synchrotron radiation in SNR shock is not applicable in the inner edge and the filamentary structure.