Hard X-Ray Emission from the Galaxy Cluster A2256.

Area of Science:

• * Astronomy and Astrophysics
• * Cosmic Ray Physics
• * Plasma Physics

Background:

• * Galaxy clusters are complex systems containing hot gas and magnetic fields.
• * Previous observations (ASCA) suggested nonthermal emission in the Coma Cluster (A2256).
• * BeppoSAX detected hard X-ray radiation up to 80 keV in the Coma Cluster spectrum.

Purpose of the Study:

• * To present evidence for nonthermal X-ray emission in the Coma Cluster (A2256).
• * To investigate the presence of multiple nonthermal components in the cluster's X-ray spectrum.
• * To constrain the intracluster magnetic field strength.

Main Methods:

• * Analysis of X-ray spectral data from the BeppoSAX satellite.
• * Statistical analysis to confirm nonthermal emission at a 4.6 sigma confidence level.
• * Comparison with existing ASCA data and theoretical models (inverse Compton).

Main Results:

• * Confirmed nonthermal emission in A2256 exceeding thermal emission.
• * Marginal consistency of the hard X-ray tail spectral index with the inverse Compton model.
• * Estimated intracluster magnetic field strengths of ~0.05 µG (northern regions) and potentially ~0.5 µG (central radio halo).

Conclusions:

• * The Coma Cluster (A2256) exhibits significant nonthermal X-ray emission.
• * The results support the presence of complex intracluster magnetic fields.
• * The findings are consistent with inverse Compton scattering of cosmic rays by intracluster magnetic fields.