Does the Galactic center GeV excess come from dark matter or pulsars?
In plain words
Fermi satellite data show extra gamma rays near $2 \times 10^{9}\ \mathrm{eV}$ from the inner galaxy, which could come from annihilating dark-matter particles or from a large hidden population of millisecond pulsars (old, fast-spinning neutron stars).
Precise statement
The Fermi-LAT excess (spectrum peaking near $1\text{ to }3\,\mathrm{GeV}$, extending $\sim 10\text{ to }20\,\mathrm{deg}$ from the Galactic center, luminosity of order $10^{37}\,\mathrm{erg/s}$) fits either dark-matter annihilation (mass $\sim 30\text{ to }70\,\mathrm{GeV}$ into b quarks, $\langle \sigma v\rangle \sim 2 \times 10^{-26}\,\mathrm{cm}^3/\mathrm{s}$) or tens of thousands of unresolved bulge millisecond pulsars. Determine which. Answer: an identification at $5\sigma$ from morphology, photon-count statistics, radio pulsar counts, or matching signals in dwarf galaxies.
What would settle it
A radio census of bulge millisecond pulsars, or a dwarf-galaxy gamma-ray detection with the predicted annihilation cross-section.
Status in the literature
Unverified note: it names recent work and was partly written without a live literature search; it awaits a check by an editor.
Through 2025, analyses disagree on whether the excess traces the stellar bulge or a spherical profile, and searches for bulge millisecond pulsars remain inconclusive.
Problems built on this one
Special cases
- Radio detection of the predicted bulge millisecond pulsar population · open
- Does the GeV excess follow the stellar bulge or a spherical halo? · open
Results
No results have been posted on this problem yet.
Post a result · how results are checked
Sign in to follow or save this problem
Comments (0)
Comments are not records: they are not signed, stamped or logged. How comments work
No comments yet.
Sign in to comment.