%0 Journal Article
%T X-ray Polarization from Black Holes: GEMS Scientific White Paper
%A Jeremy Schnittman
%A Lorella Angelini
%A Matthew Baring
%A Wayne Baumgartner
%A Kevin Black
%A Jessie Dotson
%A Pranab Ghosh
%A Alice Harding
%A Joanne Hill
%A Keith Jahoda
%A Phillip Kaaret
%A Tim Kallman
%A Henric Krawczynski
%A Julian Krolik
%A Dong Lai
%A Craig Markwardt
%A Herman Marshall
%A Jeffrey Martoff
%A Robin Morris
%A Takashi Okajima
%A Robert Petre
%A Juri Poutanen
%A Stephen Reynolds
%A Jeffrey Scargle
%A Peter Serlemitsos
%A Yang Soong
%A Tod Strohmayer
%A Jean Swank
%A Yuzuru Tawara
%A Toru Tamagawa
%J Physics
%D 2013
%I arXiv
%X We present here a summary of the scientific goals behind the Gravity and Extreme Magnetism SMEX (GEMS) X-ray polarimetry mission's black hole (BH) observing program. The primary targets can be divided into two classes: stellar-mass galactic BHs in accreting binaries, and super-massive BHs in the centers of active galactic nuclei (AGN). The stellar-mass BHs can in turn be divided into various X-ray spectral states: thermal-dominant (disk), hard (radio jet), and steep power-law (hot corona). These different spectral states are thought to be generated by different accretion geometries and emission mechanisms. X-ray polarization is an ideal tool for probing the geometry around these BHs and revealing the specific properties of the accreting gas.
%U http://arxiv.org/abs/1301.1957v1