Particle Dark Matter Searches Outside the Local Group

Area of Science:

• Cosmology and astrophysics
• Particle physics
• Astroparticle physics

Background:

• Dark matter (DM) particles may produce detectable radiation through annihilation or decay in cosmic structures.
• Detecting extragalactic DM signals is challenging due to faintness and astrophysical foregrounds.

Purpose of the Study:

• To introduce and validate a novel, powerful technique for detecting particle dark matter signals outside the Local Group.
• To compare the efficacy of this new method against existing extragalactic gamma-ray probes.

Main Methods:

• Angular cross-correlation of nongravitational signals (e.g., gamma rays) with low-redshift gravitational probes (e.g., galaxy catalogs).
• Focus on GeV-TeV dark matter and analysis of cross-correlation between the 2MASS galaxy catalog and Fermi-LAT gamma-ray maps.
• Comparison with extragalactic background energy spectrum, angular autocorrelation, and cluster emissions.

Main Results:

• The angular cross-correlation technique significantly enhances signal-to-noise ratio for extragalactic DM detection.
• This method is demonstrated to be more sensitive than other current extragalactic gamma-ray probes.
• A dark matter component, with a thermal annihilation cross section and mass between 10 and 100 GeV, provides a good fit to the observed cross-correlation data.

Conclusions:

• Angular cross-correlation is a superior method for detecting extragalactic particle dark matter signals.
• The results suggest the presence of dark matter in the 10-100 GeV mass range, warranting further investigation.
• Future data collection and dedicated analyses are crucial to confirm these findings and refine dark matter properties.