星系团弥散辐射研究 postprint

Abstract: Galaxy clusters have long been known to host diffuse, steep spectrum, syn#2;chrotron radio emission either in the central part of the cluster in the case of radio halos, or on the periphery in the case of radio relics. Detection of diffuse cluster emission across a wide range of frequency can help with understanding the formation of radio halos and radio relics, and even the formation of galaxy clusters and the Universe. We present the detec#2;tion of diffuse radio emission associated with the massive galaxy clusters SPT J2201-5956 and SPT J2023-5535 by using wide-band data from MWA at 70∼300 MHz and ATCA at 2.1 GHz. We detected a radio emission of 0.87 Mpc2 within the cluster SPT J2201-5956, and 0.9 Mpc2 in extent associated with SPT J2023-5535. We characterized the spectral index of the diffuse emission, and found SPT J2201-5956 with α = −1.68+0.27−0.27, SPT J2023-5535 with α = −1.21+0.02−0.02. The origins of the diffuse emission in SPT J2201-5956 could be dead galaxies, while the diffuse emission in SPT J2023-5535 could be a radio halo candidate.