The supernova remnant W50 at 5 GHz

• Published in: Monthly notices of the Royal Astronomical Society 1986-02, Vol.218 (3), p.393-407
• Main Authors: DOWNES, A. J. B, PAULS, T, SALTER, C. J
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Interstellar medium (ism) and nebulae in milky way; Stellar systems. Galactic and extragalactic objects and systems. The universe; Supernova remnants
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/218.3.393

Observations of the supernova remnant W50, which contains SS 433, have been made at 5 GHz with the Effelsberg 100-m telescope. These are combined with previous results at 1.7 and 2.7GHz to investigate the intrinsic linear polarization and the variation of spectral index across the source. The spectrum of W50 is typical for old shell remnants and shows no evidence for the injection of flat-spectrum fast particles from SS 433. If such injection occurs it must either be modest or be of particles with a steep energy spectrum $\,N(E)\,dE\,\sim{KE}^{-2.2}\,dE$. The northern boundary of the remnant is bright and has a slightly flatter spectrum $(\alpha \approx 0.4)$. The polarization there is strong (up to 50 per cent of the total intensity). The magnetic field direction, where it can be deduced, is tangential to the shell. The bright northern edge appears to be a typical example of compression of a large-scale interstellar magnetic field. The shell of W50 has bright regions which coincide with the position angles of the precession cone of the jets from SS 433, seen in projection.