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A Sino-German λ6 cm polarization survey of the Galactic plane - V. Large supernova remnants

2011; EDP Sciences; Volume: 529; Issue: 4 Linguagem: Inglês

1432-0746

Xiaoqing Gao, J. L. Han, W. Reich, P. Reich, Xiaohui Sun, Xiao Li,

Radio Astronomy Observations and Technology

Context. Observations of large supernova remnants (SNRs) at high frequencies are rare, but provide valuable information about their physical properties. Aims. The total intensity and polarization properties of 16 large SNRs in the Galactic p lane are investigated based on observations of the Urumqi¸ 6 cm polarization survey of the Galactic plane with an angular resolution of 9: 5. Methods. We extracted total intensity and linear polarization maps of large SNRs from the Urumqi¸ 6 cm survey, obtained their integrated flux densities, and derived the radio spectra by using these flu x densities together with previously published flux densities at various frequencies. In particular, Effelsberg¸ 11 cm and¸ 21 cm survey data were used to calculate integrated flux densities. The ¸ 6 cm polarization data also delineate the magnetic field structures of the SNRs. Results. We present the first total intensity maps at ¸ 6 cm for SNRs G106.3+2.7, G114.3+0.3, G116.5+1.1, G166.0+4.3 (VRO 42.05.01), G205.5+0.5 (Monoceros Nebula), and G206.9+2.3 (PKS 0646+06) and the first polarization measurements at ¸ 6 cm for SNRs G82.2+5.3 (W63), G106.3+2.7, G114.3+0.3, G116.5+1.1, G166.0+4.3 (VRO 42.05.01), G205.5+0.5 (Monoceros Nebula), and G206.9+2.3 (PKS 0646+06). Most of the newly derived integrated radio spectra are consistent with previous results. The new flux densities obtained from the Urumqi ¸ 6 cm, Effelsberg¸ 11 cm and¸ 21 cm surveys are crucial to determine the spectra of SNR G65.1+0.6, G69.0+2.7 (CTB 80), G93.7-0.2, and G114.3+0.3. We find that G192.8i 1.1 (PKS 0607+17) consists of background sources, H II regions, and extended diffuse emission of thermal nature, and conclude that G192.8i 1.1 is not a SNR.