A cosmic phenomenon on a colossal scale, resulting from the acceleration of a gas cloud by a black hole and its reacceleration by the shock waves from the merging of two galaxy clusters, has been observed, described and interpreted by an international collaboration of astronomers that included three Brazilians: Felipe Andrade-Santos, Vinicius Moris Placco, and Rafael Miloni Santucci.
Andrade-Santos and Placco were supported by scholarships from FAPESP, and Santucci is a participant in the Thematic Project “MOSAIC: the multi-object spectrograph for the ESO Extremely Large Telescope”, led by Silvia Cristina Fernandes Rossi and also supported by FAPESP.
“The electrons that make up the cloud initially bounce off the supermassive black hole at the centre of one of the galaxies and accelerate as a result. They are then reaccelerated by shock waves that propagate in the galaxy cluster when it collides with another cluster,” Andrade-Santos told Agência FAPESP. At present, he is a postdoctoral fellow at the Harvard-Smithsonian Centre for Astrophysics in the United States.
Galaxy clusters grow through the gravitational accretion of matter and by merging with other clusters and groups of galaxies. These mergers, which typically occur at faster-than-sound speeds, generate shock waves that propagate through the clusters for hundreds of millions of years and may reaccelerate particles previously accelerated in the galactic nuclei, where supermassive black holes are found.
Reinout J. van Weeren, Felipe Andrade-Santos, William A. Dawson, Nathan Golovich, Dharam V. Lal, Hyesung Kang, Dongsu Ryu, Marcus Brìggen, Georgiana A. Ogrean, William R. Forman, Christine Jones, Vinicius M. Placco, Rafael M. Santucci, David Wittman, M. James Jee, Ralph P. Kraft, David Sobral, Andra Stroe, Kevin Fogarty. The case for electron re-acceleration at ...(Continuar Lendo)
Study detects doubly accelerated electrons in collisions of galaxy clusters