XMM-Newton observations of the BL Lac MS 0737+7441 ?

Th Boller, M Gliozzi, G Griiths, S Sembay, R Keil, O Schwentker, W Brinkmann, S Vercellone
2000 unpublished
We report on the XMM-Newton observations of the BL Lac object MS 0737.9+7441 during the performance veriication phase. A simple power{law w t p r o vides an adequate description of the integrated spectrum in the 0.2{10 keV energy band. The photon index is slightly steeper in the EPIC pn data with ; = (2:38 0:01) compared to the EPIC MOS data (; = (2:28 0:01)). The diierence is most probably due to the present uncertainties in the calibration of the EPIC MOS and EPIC pn data sets. We report
more » ... nce for intrinsic absorption in the distant BL Lac above the Galactic column (NHGal = 3 :2 10 20 cm ;2) which i s N z=0:315 Ht = (2:70 0:20) 10 20 cm ;2 in the EPIC pn data and N z=0:315 Ht = (3 :25 0:25) 10 20 cm ;2 in the EPIC MOS data assuming neutral gas and solar abundances. The ux variations are found to be of the order of 10 %. No signiicant spectral variability is detected.