Discovery of a Featureless X-Ray Spectrum in the Supernova Remnant Shell of G330.2+1.0

We report here on the first pointed X-ray observation of the supernovaremnant (SNR) G330.2+1.0. The X-ray morphology is characterized by an extendedshell. Its X-ray spectrum is well represented by a single power-law functionwith a photon index of $\gamma\simeq 2.8$ and interstellar absorption of$n_{\rm H}\simeq2.6\times 10^{22}$[cm$^{-2}$]. We interpret this emission assynchrotron radiation from accelerated electrons at the SNR shock, as seen inSN 1006. The surface brightness of the X-ray emission is anti-correlated withthe radio emission, and the power-law spectrum is dominated at the westernshell where the radio emission is weak. The co-existence of two distinct (radiobright/X-ray faint and radio faint/X-ray bright) shells in a single supernovaremnant challenges our understanding of the particle acceleration and radiationmechanisms in different interstellar environments. The object may be a goodtarget for searching TeV gamma-rays and molecular gas surrounding the blastshock. We also report on the nature of a bright point-like source (AXJ1601-5143) to the south of the SNR.Comment: PASJ, in pres