Second Data Release from the European Pulsar Timing Array: Challenging the Ultralight Dark Matter Paradigm.

Area of Science:

• Astrophysics
• Particle Physics
• Cosmology

Background:

• Pulsar Timing Array (PTA) experiments utilize millisecond radio pulsars to detect subtle timing variations.
• Ultralight scalar or pseudoscalar particles are hypothetical dark matter candidates.
• Gravitational interaction is the assumed mechanism for dark matter's influence on baryonic matter.

Purpose of the Study:

• To constrain the properties of ultralight dark matter particles using pulsar timing data.
• To test the hypothesis that these particles constitute the entirety of local dark matter.

Main Methods:

• Analysis of the second data release from the European Pulsar Timing Array (EPTA).
• Focus on the scenario where dark matter interacts solely through gravity.
• Utilizing decade-long timing data from an ensemble of galactic millisecond pulsars.

Main Results:

• Ultralight particles with masses between 10^{-24.0} eV and 10^{-23.3} eV cannot account for 100% of the local dark matter density.
• The maximum permissible local density for these particles is constrained to be less than or equal to 0.3 GeV/cm³.

Conclusions:

• The EPTA data places significant constraints on ultralight dark matter models.
• The findings exclude certain mass ranges for dark matter if it were composed solely of these particles.