  Cluster spiral galaxies suffer catastrophic losses of the cool, neutral gas
component of their interstellar medium due to ram pressure stripping,
contributing to the observed quenching of star formation in the disk compared
to galaxies in lower density environments. However, the short term effects of
ram pressure on the star formation rate and AGN activity of galaxies undergoing
stripping remain unclear. Numerical studies have recently demonstrated cosmic
rays can dramatically influence galaxy evolution for isolated galaxies, yet
their influence on ram pressure stripping remains poorly constrained. We
perform the first cosmic-ray magneto-hydrodynamic simulations of an $L_{*}$
galaxy undergoing ram pressure stripping, including radiative cooling,
self-gravity of the gas, star formation, and stellar feedback. We find the
microscopic transport of cosmic rays plays a key role in modulating the star
formation enhancement experienced by spirals at the outskirts of clusters
compared to isolated spirals. Moreover, we find that galaxies undergoing ram
pressure stripping exhibit enhanced gas accretion onto their centers, which may
explain the prevalence of AGN in these objects. In agreement with observations,
we find cosmic rays significantly boost the global radio emission of cluster
spirals. Although the gas removal rate is relatively insensitive to cosmic ray
physics, we find that cosmic rays significantly modify the phase distribution
of the remaining gas disk. These results suggest observations of galaxies
undergoing ram pressure stripping may place novel constraints on cosmic-ray
calorimetry and transport.

Astrophysics of Galaxies