S E M I N A R I

Departament d'Astronomia i Astrofísica
Universitat de València

    M87: A Laboratory for Astrophysical Processes

Philip E. Hardee

University of Alabama


Seminari del departament d'Astronomia i AstrofĂ­sca

Dijous 10 desembre 2009

15:00


Resum

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Some AGN accelerate particles to energies exceeding 10^{12} electron Volts (eV) and are bright sources of very-high-energy (VHE) gamma-ray emission. However, it is not yet known where the VHE emission originates or what provides the mechanism for particle acceleration to very high energies. Firstly I report on radio and VHE observations of the radio galaxy M 87 that reveal a period of extremely strong gamma-ray flares accompanied by a strong increase in the radio flux. The results imply that particles must be accelerated to very high energies in the immediate vicinity of the black hole. Secondly I present new numerical simulation studies of the current driven instability (CDI) that could provide conversion of magnetic energy to plasma jet bulk kinetic energy and could also provide particle acceleration to the very high energies required by the observed emission.