X-ray Polarization from Black Holes: GEMS Scientific White Paper
astro-ph.HE
/ Authors
Jeremy Schnittman, Lorella Angelini, Matthew Baring, Wayne Baumgartner, Kevin Black, Jessie Dotson, Pranab Ghosh, Alice Harding, Joanne Hill, Keith Jahoda
and 20 more authors
Phillip Kaaret, Tim Kallman, Henric Krawczynski, Julian Krolik, Dong Lai, Craig Markwardt, Herman Marshall, Jeffrey Martoff, Robin Morris, Takashi Okajima, Robert Petre, Juri Poutanen, Stephen Reynolds, Jeffrey Scargle, Peter Serlemitsos, Yang Soong, Tod Strohmayer, Jean Swank, Yuzuru Tawara, Toru Tamagawa
/ Abstract
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.