Discovery of a new supernova remnant G21.8−3.0. Issue 2 (2nd March 2020)

• Record Type: Journal Article
• Authors: Gao, X Y; Reich, P; Reich, W; Hou, L G; Han, J L
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 493:Issue 2(2020)
• Page Start: 2188
• Page End: 2194
• Publication Date: 2020-03-02
• Subjects: methods: observational -- ISM: supernova remnants -- radio continuum: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa419
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Sensitive radio continuum surveys of the Galactic plane are ideal for discovering new supernova remnants (SNRs). From the Sino-German λ6-cm polarization survey of the Galactic plane, an extended shell-like structure has been found at ℓ = 21${^{\circ}_{.}}$ 8, b = −3${^{\circ}_{.}}$ 0, which has a size of about 1°. New observations were made with the Effelsberg 100-m radio telescope at λ11 cm to estimate the source spectrum, together with Urumqi λ6-cm and Effelsberg λ21-cm data. The spectral index of G21.8−3.0 was found to be α = −0.72 ± 0.16. Polarized emission was mostly detected in the eastern half of G21.8−3.0 at both λ6 and λ11 cm. These properties, together with the Hα filament along its northern periphery and the lack of infrared emission, indicate that the emission is non-thermal, as is usual in shell-type SNRs.