Search for Axionic Dark Matter Using the Magnetar PSR J1745-2900

Area of Science:

• Astrophysics
• Particle Physics
• Cosmology

Background:

• Dark matter remains one of the biggest mysteries in physics.
• Axions are hypothetical particles proposed as a dark matter candidate.
• Magnetars, like PSR J1745-2900, possess extremely strong magnetic fields.

Purpose of the Study:

• To search for axion-photon conversion signals from the magnetosphere of the Galactic Center magnetar PSR J1745-2900.
• To constrain axion properties, specifically the axion-photon coupling constant (g_{aγγ}) and mass.
• To test axion models as a component of dark matter.

Main Methods:

• Utilized spectral data from the Karl G. Jansky Very Large Array (VLA).
• Analyzed radio spectra for characteristic features indicative of axion-photon conversion.
• Applied a hybrid model of the magnetar and dark matter density profiles to set limits.

Main Results:

• No significant spectral features attributable to axion-photon conversion were detected.
• Excluded axion models with g_{aγγ} > 6-34×10⁻¹² GeV⁻¹ for specific mass ranges (4.2-8.4, 18.6-26.9, 33.0-41.4, 53.7-62.1, and 126.0-159.3 μeV).
• Under a dark matter cusp scenario, excluded models with g_{aγγ} > 6-34×10⁻¹⁴ GeV⁻¹ for masses >33 μeV.

Conclusions:

• The search places stringent limits on axion properties, ruling out certain parameter spaces for axion dark matter.
• Future observations could improve these limits by modeling stimulated emission effects.
• This study contributes to the ongoing effort to identify the nature of dark matter.