* Background characteristics

* Galactic 511 keV (annihilation of positron) emission
    - see Jean, Knoedlseder, Lonjou et al., 2003, A&A Letters, L55, 407
    - see Knoedlseder, Lonjou, Jean et al., 2003, A&A Letters, 411, 457
    - see Teegarden, Watanabe, Jean et al., 2005, ApJ, 621, 296
    - see Knoedlseder, Jean, Lonjou et al., 2005, A&A
    - see Jean, Knoedlseder, Gillard et al., 2006, A&A
    - see my presentation done at the IEEC-Barcelona (21 september 2005)
    - see Weidenspointner et al., 2006, A&A
    - see Weidenspointner et al., 2008, Nature