Max Planck Inst Extraterr Phys, D-85748 Garching, Germany
; Acad Sinica, Inst High Energy Phys, Lab Cosm Ray & High Energy Astrophys, Beijing 100039, Peoples R China
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 6.8 10(-12) erg cm(-2) s(-1) in the 0.7-10 keV band, and a column density of 17.9(-2.5)(+2.8) 10(21) cm(-2). The high absorption column density indicates a distance close to the radius of the galaxy. The 0.7-10.0 keV X-ray luminosity of G54.1+0.3 is 1.4 10(35)d(10)(2), erg s(-1) where d(10) is the distance in 10 kpc. 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 0.1-2.4 keV range is about 2.1 10(34)d(10)(2) erg s(-1). The X-ray jet is consistent with the radio extension of G54.1+0.3 to the north-east in both direction and position.