Probing the Fermi-LAT GeV Excess with Gravitational Waves.

If the gamma-ray excess towards the inner Galaxy (GCE) detected in Fermi-LAT data is due to millisecond pulsars (MSPs), one expects an associated gravitational wave (GW) signal, whose intensity exceeds the disk MSP population emission by an order of magnitude. We compute the expected GW counterpart of the bulge MSP population based on fits of the GCE, and estimate the sensitivity reach of current and future terrestrial GW detectors. The bounds on the average population ellipticity ϵ are competitive with the existing ones derived by LIGO/Virgo towards known MSPs. With a 10-yr data taking in current LIGO/Virgo configuration, one would detect a signal at the level ϵ≃10^{-7}, while ϵ≃10^{-8} would be attainable with a similar data taking period with a third generation GW detector. This sensitivity should be sufficient for crucial diagnostics on the GCE interpretation in terms of MSPs.

Searching for Primordial Black Holes in the Radio and X-Ray Sky.

We model the accretion of gas onto a population of massive primordial black holes in the Milky Way and compare the predicted radio and x-ray emission with observational data. We show that, under conservative assumptions on the accretion process, the possibility that O(10)M_{⊙} primordial black holes can account for all of the dark matter in the Milky Way is excluded at 5σ by a comparison with a Very Large Array radio catalog at 1.4 GHz and at ≃40σ by a comparison with a Chandra x-ray catalog (0.5-8 keV). We argue that this method can be used to identify such a population of primordial black holes with more sensitive future radio and x-ray surveys.

Significant enhancement of neutralino dark matter annihilation from electroweak bremsstrahlung.

Indirect searches for the cosmological dark matter have become ever more competitive during the past years. Here, we report the first full calculation of leading electroweak corrections to the annihilation rate of supersymmetric neutralino dark matter. We find that these corrections can be huge, partially due to contributions that have been overlooked so far. Our results imply a significantly enhanced discovery potential of this well motivated dark matter candidate with current and upcoming cosmic ray experiments, in particular for gamma rays and models with somewhat small annihilation rates at the tree level.