The imaging spectrometer SPI on board ESA's INTEGRAL observatory provides us
with an unprecedented view of positron annihilation in our Galaxy. The first
sky maps in the 511 keV annihilation line and in the positronium continuum from
SPI showed a puzzling concentration of annihilation radiation in the Galactic
bulge region. By now, more than twice as many INTEGRAL observations are
available, offering new clues to the origin of Galactic positrons. We present
the current status of our analyses of this augmented data set. We now detect
significant emission from outside the Galactic bulge region. The 511 keV line
is clearly detected from the Galactic disk; in addition, there is a tantalizing
hint at possible halo-like emission. The available data do not yet permit to
discern whether the emission around the bulge region originates from a
halo-like component or from a disk component that is very extended in latitude.Comment: to be published in the proceedings of the 6th INTEGRAL Workshop "The
Obscured Universe" (3-7 July 2006, Moscow
