Indirect dark matter searches in the dwarf satellite galaxy Ursa Major II with the MAGIC Telescopes

TL;DR

This study used the MAGIC telescopes to observe the dark-matter-rich dwarf galaxy Ursa Major II, setting new constraints on dark matter annihilation cross-sections at very high energies between 100 GeV and 100 TeV.

Contribution

It provides the first deep, high-energy gamma-ray observations of UMaII with the full likelihood analysis, improving constraints on dark matter annihilation.

Findings

Set the most stringent limits on dark matter annihilation cross-section at TeV energies from dwarf galaxies.

Analyzed nearly 100 hours of data with spectral information for optimal sensitivity.

Extended the search for dark matter signals to a wider mass range (100 GeV to 100 TeV).

Abstract

The dwarf spheroidal galaxy Ursa Major II (UMaII) is believed to be one of the most dark-matter dominated systems among the Milky Way satellites and represents a suitable target for indirect dark matter (DM) searches. The MAGIC telescopes carried out a deep observation campaign on UMaII between 2014 and 2016, collecting almost one hundred hours of good-quality data. This campaign enlarges the pool of DM targets observed at very high energy (E$\gtrsim$50GeV) in search for signatures of dark matter annihilation in the wide mass range between $\sim$100 GeV and $\sim$100 TeV. To this end, the data are analyzed with the full likelihood analysis, a method based on the exploitation of the spectral information of the recorded events for an optimal sensitivity to the explored dark matter models. We obtain constraints on the annihilation cross-section for different channels that are among the most robust and stringent achieved so far at the TeV mass scale from observations of dwarf satellite galaxies.