Magnetic fields and relativistic electrons fill entire galaxy cluster

© ROSAT/LOFAR/SDSS/Botteon et al., 2022, Science Advances/Frits Sweijen

The deepest images ever produced of a galaxy cluster at low frequencies have been obtained combining 18 nights of LOFAR observations: 75h at 50 MHz and 72h at 150 MHz.

The deep data shows a giant (5 Mpc) envelope or radio emission that embeds the entire galaxy cluster Abell 2255. This emission, highlighted in purple in the composite image, is generated by relativistic electrons propagating in the weak magnetic fields in the cluster periphery. The image is about 18 million by 18 million light years in size. From Earth, the image covers a region of the sky the size of four full moons.

Paper link (open access): https://www.science.org/doi/10.1126/sciadv.abq7623