Indirect Dark Matter Detection Limits from the Ultra-Faint Milky Way Satellite Segue 1

TL;DR

This paper uses new kinematic data from the ultra-faint satellite Segue 1 to set limits on dark matter annihilation, combining gamma-ray, neutrino, and velocity dispersion analyses to probe dark matter properties.

Contribution

It provides the first comprehensive limits on dark matter annihilation from Segue 1 using multiple detection channels and models its dark matter distribution in detail.

Findings

Gamma-ray observations exclude certain dark matter models.

Potential neutrino signals could be detected in optimistic scenarios.

Constraints on Sommerfeld enhancement models are established.

Abstract

We use new kinematic data from the ultra-faint Milky Way satellite Segue 1 to model its dark matter distribution and derive upper limits on the dark matter annihilation cross-section. Using gamma-ray flux upper limits from the Fermi satellite and MAGIC, we determine cross-section exclusion regions for dark matter annihilation into a variety of different particles including charged leptons. We show that these exclusion regions are beginning to probe the regions of interest for a dark matter interpretation of the electron and positron fluxes from PAMELA, Fermi, and HESS, and that future observations of Segue 1 have strong prospects for testing such an interpretation. We additionally discuss prospects for detecting annihilation with neutrinos using the IceCube detector, finding that in an optimistic scenario a few neutrino events may be detected. Finally we use the kinematic data to model the Segue 1 dark matter velocity dispersion and constrain Sommerfeld enhanced models.