Chandra observations of a nonthermal supernova remnant candidate AX J1843.8-0352 and its surroundings

We present the Chandra results of AX J1843.8-0352, a supernova remnant (SNR) recently identified with ASCA. Chandra spatially resolved two components from this SNR: one nonthermal and one thermal. The morphology of the nonthermal component is clumpy and elliptical, elongated from the north to the south with a mean diameter of about 9'. The spectrum is fitted with a power-law model of photon index 2.1, and the east rim is associated with the nonthermal radio sources C and F. Therefore, the nonthermal component is probably synchrotron X-rays produced by energetic electrons accelerated at the shell of the SNR. The thermal component is the brightest clump located within the nonthermal component and shows the spectrum of a thin plasma of about 0.7 keV temperature. A notable discovery is its peculiar morphology; a head of 50" x 30" size near the southeast rim of the SNR and a 30" long "jet'' pointing to the southwest. Although this emission is associated with the western part of the radio source F, the absorption is 2 times larger than that of the nonthermal X-rays or the bulk of the SNR emission. Therefore, it is unclear whether this peculiar plasma is a thermal component associated with AX J1843.8-0352, a Galactic source located in the far side of our Galaxy, or an extragalactic source.