Diffuse radio emission in Abell 2256 was detected above 3 σ with DRAO observations at 1420 MHz. The halo size is ~13'×10' (~1h 50 -1) in full extent and is elongated along a position angle of about 112°. The total flux density contained in the halo is 30±10 mJy at 1420 MHz and its spectral index is -2.04±0.04, showing no evidence for steepening up to 1420 MHz. Using the size estimate, yields a more reliable equipartition magnetic field strength which is 0.34(1 + k)2/7 μG. In addition, five new radio sources are identified.

Here I report the confirmation of a long-term modulation of a period of 92 + 21 − 13 years with the "time-delay correlation" method on the sunspot data compiled over the last a total of 289 years. This periodicity better specifies the cycle which falls pretty well within Gleissberg cycle, and clearly contrasts with the 55 year grand cycle which Yoshimura (1979) claimed. It is argued that the period-amplitude diagram method. which Yoshimura used, ana lysed peak amplitudes only so that a large number of data were disregarded, and thus was more susceptible to a bias. The planetary tidal force on Sun as for the possible cause to the solar activity was investigated and its possibility was ruled out in view of no period correlation between them.

In the presence of synchrotron losses, diffusion of an ensembel of relativistic particles in an intraculster medium is investigated. The diffusion coefficient in the medium is found to be constrained by 28.8 ± 0.4 ≤ L o g D ≤ 30.5 ± 0.4 c m 2 s − 1 with the energy dependency of D 0 ε μ of μ = 0.4 ± 0.2 as the previous observations suggested. As an important implication of the result, the brightest head-tail radio source NGC 4869, whose radio tail structure is indicative for its orbit within the cluster core, is considered to be the major contributor of particles for the formation of the Coma radio halo.