Understanding the Last Mile - Physics of the Accretion Column

Peter Kretschmar, Peter A. Becker, Dipankar Bhattacharya, Isabel Caballero, Thomas Dauser, Carlo Ferrigno, Dmitry Klochkov, Ingo Kreykenbohm, Osamu Nishimura, Katja Pottschmidt, Richard E. Rothschild, Andrea Santangelo, Gabriele Schönherr, Fritz-Walter Schwarm, Rüdiger Staubert, Slawomir Suchy, Brent West, Jörn Wilms, Michael Wolff, Kenneth Wolfram

Published 2012-11-16Version 1

Accreting X-ray pulsars are among the best observed objects of X-ray astronomy with a rich data set of observational phenomena in the spectral and timing domain. While the general picture for these sources is well established, the detailed physics behind the observed phenomena are often subject of debate. We present recent observational, theoretical and modeling results for the structure and dynamics of the accretion column in these systems. Our results indicate the presence of different accretion regimes and possible explanations for observed variations of spectral features with luminosity.