Astronomy & Astrophysics Seminar: Fermi Bubbles as signatures of star-formation driven outflow in our Galaxy

Abstract:

​Modelling of emission from multiphase galactic outflows is important to decipher the feedback processes in galaxies. Fermi Bubbles (FBs) are excellent laboratories for such studies as they shine in radio, x-ray, gamma rays and also show kinematic signatures in UV absorption. Using hydrodynamical simulations, we show that these bubbles can arise from a star formation activity at the Galactic Centre with a star formation rate of 0.3-0.5 Msun/yr sustaining over a time scale of ~30 Myrs. By modelling the X-ray emission related to the FBs, we constrain the central halo density in our Galaxy to be ~3e-3 m_p/cc. Our modelling of radio emission suggests that the magnetic field inside these bubbles is ~ 3-5 \muG, and is sufficient to give rise to the observed gamma-ray spectrum by inverse Compton scattering of CMB by cosmic rays. Our model also provides explanation of the observed kinematics of absorption lines through the FBs.

Seminar Organizer: Prof. Sara Beck