%0 Journal Article
%T XMM - Newton observations of Markarian 421
%A W. Brinkmann
%A S. Sembay
%A R. G. Griffiths
%A G. Branduardi-Raymont
%A M. Gliozzi
%A Th. Boller
%A A. Tiengo
%A S. Molendi
%A S. Zane
%J Physics
%D 2000
%I arXiv
%R 10.1051/0004-6361:20000084
%X The BL Lac object Mrk 421 was observed on May 25, 2000 during the XMM - Newton CAL/PV phase. The high throughput of the X-ray telescopes and the spectral capabilities of the instruments allow an uninterrupted temporal and spectral study of the source with unprecedented time resolution. Mrk 421 was found at a relatively high state with a 2-6 keV flux of (1.3 - 1.9)E-10 erg cm**-2 s **-1. The observed intensity variations by more than a factor of three at highest X-ray energies are accompanied by complex spectral variations with only a small time lag (tau = 265 {+116} {-102} seconds) between the hard and soft photons. The (0.2-10) keV spectrum can be well fitted by a broken power law and no absorption structures are found in the source spectrum at the high spectral resolution of the transmission gratings.
%U http://arxiv.org/abs/astro-ph/0011193v1