Wednesday, December 1, 2010 - 3:15pm
Roland Crocker (MPI-K):
"Wild at Heart: the Particle Astrophysics of the Galactic Centre"
Abstract. I describe the high-energy astrophysics of the inner ~200 pc of the Galaxy. This is ultimately driven by the on-going massive star formation that occurs in this region. Our recent modelling shows that the supernovae exploding here every few thousand years inject enough power to i) sustain the steady-state, in situ population of cosmic rays (CRs) required to generate the region's non-thermal radio and diffuse TeV gamma-ray emission (as observed by the HESS telescope); ii) drive a powerful wind that advects non-thermal particles out of the inner GC; iii) accelerate the primary protons and heavier ions which, continuously advected to very large scales (up to ~10 kpc) above and below the plane over timescales approaching the age of the Galaxy, generate the very-extended regions of hard-spectrum gamma-ray emission recently detected by the Fermi telescope (and corresponding microwave structures detected by WMAP -- the "Fermi bubbles" and "WMAP haze"). Our modelling bounds the magnetic field amplitude in the inner few degrees of the Galaxy to the range 60 < B/microG < 400 and predicts a region of very extended ~TeV gamma-ray and neutrino emission surrounding the GC, the latter constituting a very promising source for a future, km^3-class Northern Hemisphere neutrino telescope. I speculate that the wind we identify plays a crucial role in advecting low-energy positrons from the Galactic nucleus into the bulge, there by explaining the extended morphology of the 511 keV line emission.