2001A&A...370..570L

We present analyses of the ROSAT PSPC and the ASCA SIS and GIS observations of the Crab-like supernova remnant (SNR) G54.1+0.3. The spectrum is best fitted by a power law model with a photon index of -1.9^+0.2_–0.2, absorbed energy flux of 6.8x10^–12erg/cm²/s in the 0.7-10 keV band, and a column density of 17.9^+2.8_–2.5x10²¹cm^–2. The high absorption column density indicates a distance close to the radius of the galaxy. The 0.7-10.0keV X-ray luminosity of G54.1+0.3 is 1.4x10³⁵d₁₀²erg/s, where d₁₀ is the distance in 10kpc. With an image restoration method, we have deconvolved the X-ray image of the remnant. There is evidence for an X-ray jet pointing to the north-east with a length of about 40" measured from the center of the nebula. Its X-ray luminosity in the 0.1-2.4keV range is about 2.1x10³⁴d₁₀²erg/s. The X-ray jet is consistent with the radio extension of G54.1+0.3 to the north-east in both direction and position.