Special Joint Astro-Plasma Seminar: M82 starburst galaxy: possible origin of the northern hot spot

Toshikazu Ebisuzaki (RIKEN)
Thursday, November 16, 2017
1:00 pm
FRH 4135

M82 is a starburst galaxy, which undergoes a burst of star formation triggered by the encounter with the neighbouring galaxy M81. It harbours an intermediate mass black hole, M82 X-1 with the mass of $100 \sim 10,000 M_{\odot}$. The X-ray luminosity of M82 X-1 is as high as $10^{41} {\rm erg s^{-1}}$, so that its mass must be higher than $1000 M_{\odot}$, if we assume the sub-Eddington luminosity. According to the bow wake linear accerelation theory developed by Ebisuzaki and Tajima (2014), charged particles in the relativistic jets are linearly accelerated by the pondermotive force of intense Alfven waves emitted from the magnetic eruption of the accretion disk around the blackhole.

The energies of accelerated protons in the jets can reach $10^{20}$ eV, while accelerated electrons emits gamma-rays due to the interaction with magnetic disturbances. The protons produced by M82 X-1 by the bow wake linear accerelation can explain the northern hot spot in the sky distribution of Ultra High Energy Cosmic-Rays reported by TA group, if we take into account the deflection by the intergalactic magnetic field between M82 and the Milky Way galaxy. According to the observation by Fermi gamma-ray observatory, M82 is a source of  gamma-rays (1-100 GeV), which is also consistent with the bow wake linear accerelation theory.


Toshiki Tajima