Speaker
Description
The correct description of cosmic ray transport in the circumgalactic media of galaxies and in the intracluster gas suffusing larger halos is an active area of research. I will outline results we have obtained from a high-level treatment of cosmic ray injection, transport, and energy loss in dark matter halos. There are three limiting cases: i) cosmic rays are accumulated over cosmic timescales and come to represent a total energy close to the gravitational binding energy of the CGM or ICM gas; ii) cosmic rays (especially if trapped by slow transport in higher density CGM or ICM gas) lose energy via pp interactions and do not accumulate to represent a large energy reserve but, in this case, tend to over-produce gamma-rays in the Fermi band; iii) cosmic rays lose energy to streaming + damping of the excited waves but, in this case, may act as an important source of localised gas heating. I will delimit the regions of parameter space allowed by observational constraints considered in toto and outline implications of our model for hadronic gamma-ray emission from the CGM of local L_star galaxies, including the Milky Way and M31.
