Measuring the smearing of the Galactic 511-keV signal: positron propagation or supernova kicks?

Here, we attempt to constrain the propagation length of positrons by a spatial analysis 511-keV line and ortho-positronium (ortho-Ps) continuum in Milky Way bulge from 15 yr INTEGRAL/SPI data. Weidenspointner et al. (2006) reconstructed an image energy band 410–500 keV, where ortho-Ps is dominant, found asymmetric component. For first time, perform spectrally resolved study that extends lower energies, >200 keV. This leads improvement statistical quality boosts discriminant power existing data because expected flux about 4–4.5 times larger than 511 keV alone. Including allows us compare various tracers positron annihilation use stellar templates, dark matter (DM) profiles, or disc gas maps, combinations thereof. Among most...