Detection of X-ray flares from AX J1714.1-3912, the unidentified source near RX J1713.7-3946

TL;DR

This study used Suzaku and Chandra observations to analyze the X-ray source near SNR RX J1713.7-3946, revealing it as a point source with rapid variability, high absorption, and a potential link to a supergiant fast X-ray transient.

Contribution

The paper clarifies the nature of AX J1714.1-3912, identifying it as a point source with specific spectral and temporal properties, and suggests its possible association with a supergiant fast X-ray transient.

Findings

No diffuse emission associated with AX J1714.1-3912.

Detected rapid variability (~1 ks) and high intrinsic absorption.

X-ray flux decreased by 1-2 orders of magnitude over years.

Abstract

Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1-3912, near the SNR RX J1713.7-3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the ~4.5 yr time separation between the two observations. We found that there is no diffuse emission associated with AX J1714.1-3912, which is instead the point-like source CXOU J171343.9-391205. We discovered rapid time variability (timescale ~1 ks), together with a high intrinsic absorption and a hard nonthermal spectrum (power law with photon index Gamma~1.4). We also found that the X-ray flux of the source drops down by 1-2 orders of magnitude on a timescale of a few years. Our results suggest a possible association between AX J1714.1-3912 and a previously unknown supergiant fast X-ray transient, although further follow-up observations are necessary to prove this association definitively.