Diffuse radio sources in clusters of galaxies:models and long-wavelength radio observations

摘要

Clusters of galaxies contain several types of diffuse radio sources with very steep radio spectra which are associated with the cluster environment, including central radio bubbles, cluster radio relics, and cluster radio halos. Radio halos and relics are found only in merging clusters. Cluster radio relics may be produced by particle acceleration in merger shocks, while radio halos, may result from electron re-acceleration by turbulence produced by mergers. Secondary production of electrons and positrons by hadronic interactions also plays a role. If cluster radio halos and relics are related to mergers, then deep low frequency radio surveys . could detect 1000's of clusters. Long-wavelength radio observations have a great potential to help us understand clusters and large scale structure, and can provide a diagnostic of cluster mergers, which affect the use of clusters in cosmological and dark energy studies.