Peering into the Milky Way by FAST: IV Identification of two new Galactic supernova remnants G203 1+6 6 and G206 7+5 9 by X. Y. Gao et al. on Wednesday 30 November

A 5$^{\circ}$ $\times$ 7$^{\circ}$ sky area containing two large radio

structures of G203.1+6.6 and G206.7+5.9 with a size of about 2.5$^{\circ}$ and

3.5$^{\circ}$ 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 be $\beta$ $\sim$ $-$2.6 to $-$2.7. Polarized

emission is detected from the archival Effelsberg $\lambda$11 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 HI structures, the kinematic distance to this new SNR is estimated to

be about 440 pc, placing it in the Local Arm.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.11408v2