  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.
