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 { cm ^ { -2 } } \lesssim N _ { H } \lesssim 10 ^ { 23 } \mathrm { cm ^ { -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 .