Discovery of supernova remnants in the Sino-German 6cm polarization survey of the Galactic plane

TL;DR

The paper reports the discovery of four new supernova remnants in the Galactic plane using the Sino-German 6cm polarization survey, highlighting the survey's effectiveness in identifying faint, extended SNRs through polarization and spectral analysis.

Contribution

It introduces four newly identified supernova remnants using 6cm polarization data combined with multi-wavelength observations, demonstrating the survey's capability to find previously unknown faint SNRs.

Findings

Discovered four new supernova remnants G178.2-4.2, G25.1-2.3, G152.4-2.1, G190.9-2.2.

G178.2-4.2 shows a polarized shell structure.

G25.1-2.3 is estimated to be about 3 kpc away.

Abstract

The Sino-German 6cm polarization survey has mapped in total intensity and polarization intensity over an area of approximately 2200 square degrees in the Galactic disk. This survey provides an opportunity to search for Galactic supernova remnants (SNRs) that were previously unknown. We discovered the new SNRs G178.2-4.2 and G25.1-2.3 which have non-thermal spectra, using the 6cm data together with the observations with the Effelsberg telescope at 11 cm and 21 cm. Both G178.2-4.2 and G25.1-2.3 are faint and have an apparent diameter greater than 1deg. G178.2-4.2 shows a polarized shell. HI data suggest that G25.1-2.3 might have a distance of about 3 kpc. The 6cm survey data were also very important to identify two other new SNRs, G152.4-2.1 and G190.9-2.2.