The sky distribution of 511 keV positron annihilation line emission as measured with INTEGRAL/SPI

G. Weidenspointner, J. Knödlseder, P. Jean, G. K. Skinner, P. Von Ballmoos, J. P. Roques, G. Vedrenne, P. Milne, B. J. Teegarden, R. Diehl, A. Strong, S. Schanne, B. Cordier, Ch Winkler

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)25-32
Number of pages8
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number622 SP
StatePublished - Jul 2006
Event6th Integral Workshop - The Obscured Universe - Moscow, Russian Federation
Duration: Jul 2 2006Jul 8 2006


  • Galactic 511 keV line emission
  • Positron annihilation

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science


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