  Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed
the presence of a strong 511 KeV gamma-ray line emission from the bulge, which
require an intense source of positrons in the galactic center. These
observations are hard to account for by conventional astrophysical scenarios,
whereas other proposals, such as light DM, face stringent constraints from the
diffuse gamma-ray background. Here we suggest that light superconducting
strings could be the source of the observed 511 KeV emission. The associated
particle physics, at the ~ 1 TeV scale, is within reach of planned accelerator
experiments, while the distinguishing spatial distribution, proportional to the
galactic magnetic field, could be mapped by SPI or by future, more sensitive,
satellite missions.
