Abstract

Contributed Talk - Splinter StarFormation   (MW-1250)

A multi-frequency perspective on Cosmic Ray signatures in Nearby Galaxies

C. J. Riseley
AIRUB

It is well-established that radio continuum provides both an unobscured tracer of star formation as well as a window into the magnetic field strength in galaxies. In this context, understanding the injection and propagation of cosmic rays (CR) in the interstellar medium, and how these process couple to star formation activity — as well as a galaxy’s star formation history — is crucial to completing the picture of galactic feedback processes. Low-frequency radio observations provide a unique view onto the non-thermal ISM of galaxies, tracing aged CR electrons and diffuse synchrotron emission that are largely inaccessible at GHz frequencies. However, it is only through the union of different instruments across the radio and optical/UV/IR windows that we can explore the injection and propagation of CR associated with star formation. In this vein, the broad spectral coverage and unique sensitivity to low surface brightness emission offered by the combination of data from the MWA, ASKAP and MeerKAT, provides unparalleled information into the non-thermal component of the ISM of nearby galaxies. In this talk, I will present new results from detailed multi-frequency and multi-wavelength observations of the spectacular nearby galaxies NGC 1313 and NGC 55. I will discuss how these observations shape our understanding of the connection between the thermal and non-thermal components of the ISM, how star formation activity couples to the magnetic field, as well as what we can learn about the transport of CR in the ISM.