X-ray lobes of W50/SS433 system Original Research Article

The X-ray lobel lie on both sides (east and west) of SS433, and are presumably produced by the interaction of the jets of SS433 with the surrounding SNR W50. The non-thermal nature of the east lobe has been reported by Yamauchi et al. (1994) using the ASCA data. With the further ASCA observations, we studied the spectra and morphology of both the east and west lobes in detail. Their spectra have no emission lines, and are best described by power-law models with interstellar absorption. The X-ray emission becomes softer on the both sides with the distance from SS433. The surface brightness peaks closer to SS433 in the high-energy band than in the low energy band, suggesting that the high energy electrons in the X-ray lobes lose energies by synchrotron emission as they travel away from SS433. We estimate the magnetic field and the total energy of the high energy electrons to be a few μG and ∼ 1046 erg respectively, where equipartition in energy between the relativistic electrons and magnetic field is assumed.