Observations of the X-ray Afterglows of GRB011211 and GRB001025 by   XMM-Newton
  We present the XMM-Newton observations of X-ray afterglows of the gamma-ray bursts GRB 011211 and GRB 001025. For GRB 011211 XMM detected fading X-ray object with an average flux in 0.2-10 keV declining from 2.7$\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$ during the first 5 ks of 27-ks observation to 1.0$\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$ toward the end of the observation. The spectrum of the afterglow can be fit to a power law with alpha=2.16$\pm$0.03 modified for the Galactic absorption. No significant evolution of spectral parameters has been detected during the observation. Similar X-ray spectrum with alpha=2.01$\pm$0.09 has been observed by the XMM from the GRB 001025. The non-detection of any extra absorption in these spectra above the Galactic value is an interesting fact and may impose restrictions to the favorable GRB models involving burst origin in star-forming regions. Finally we discuss soft X-ray lines from GRB 011211 reported by Reeves et al.(2002) and conclude that there is no definitive evidence for the presense of these lines in the spectrum. 
Konstantin N. Borozdin, Sergey P. Trudolyubov (Los Alamos National   Laboratory and IKI RAN)