摘要
A 5°×7°sky area containing two large radio structures of G203.1+6.6 and G206.7+5.9 with a size of about 2.°5 and 3.°5 respectively is scanned by using the L-band 19-beam receiver of the Five-hundred-meter Aperture Spherical radio Telescope(FAST).The FAST L-band receiver covers a frequency range of 1.0-1.5 GHz.Commissioning of the receiving system,including the measurements of the half-power beam width,gain,and main-beam efficiency is made by observing the calibrators.The multi-channel spectroscopy backend mounted to the receiver allows an in-band spectral-index determination.The brightness-temperature spectral indices of both objects are measured to beβ~-2.6 to-2.7.Polarized emission is detected from the archival Effelsbergλ11 cm data for all the shell structures of G203.1+6.6 and G206.7+5.9.These results clearly indicate a non-thermal synchrotron emitting nature,confirming that G203.1+6.6 and G206.7+5.9 are large shell-type supernova remnants(SNRs).Based on morphological correlation between the radio continuum emission of G206.7+5.9 and the H i structures,the kinematic distance to this new SNR is estimated to be about 440 pc,placing it in the Local Arm.
基金
supported by the National Key R&D Program of China(Grant Nos.2021YFA1600401,and 2021YFA1600400)
the National Natural Science Foundation of China(Grant No.11988101)
and the National SKA Program of China(Grant No.2022SKA0120103)
the CAS-NWO Cooperation Program(Grant No.GJHZ1865)
the Open Project Program of the Key Laboratory of FAST,NAOC,Chinese Academy of Sciences
supported by the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS,and the Science&Technology
supported by the National Natural Science Foundation of China(Grant No.12003044)。
