HINTS that dark matter is crashing and burning in the centre of the Milky Way might themselves be going up in smoke.
An unexpectedly bright gamma-ray glow was first spotted at the centre of our galaxy in 2010, in data from the Fermi Gamma-Ray Space Telescope. Physicists interpreted it as the debris from particles of mysterious dark matter – thought to make up most of the stuff in the universe – crashing together and annihilating each other.
But this year, two teams found thousands of previously unnoticed pulsars – corpses of dead stars – that could account for the brightness.
If the signal is down to dark matter it should be seen in other galaxies, such as dwarf galaxies. But when Kevork Abazajian at the University of California, Irvine, and colleagues analysed data from nearby dwarf galaxies, they found no such signal (arxiv.org/abs/1510.06424).
"If the dwarf limits were this strong in 2010-12 when we first started working on the dark matter interpretation of the galactic centre excess, we may have not taken it as seriously," he says.