Speaker
Description
Globular clusters (GCs) are long-lived relics of galaxy assembly and retain important information about merger history, chemical enrichment, and the build-up of galactic bulges and halos. We investigate the prospect that their high-energy emission may provide a new, complementary way to probe this evolution. In our scenario, millisecond pulsars (MSPs) in GCs power persistent GeV emission, while electrons re-accelerated in communal stellar/pulsar-wind termination shocks generate TeV gamma-rays through inverse-Compton scattering as they propagate into GC magnetotails. We model the integrated GeV–TeV output from GC systems embedded in galaxies with different evolutionary pathways, including quiescent growth, minor-merger-driven assembly, and major mergers or strong interactions. The predicted gamma-ray signal depends on the total GC population, and its radial and metallicity distribution. Centrally concentrated, metal-rich GC populations formed in major mergers can produce prominent GeV and TeV signatures, whereas GC systems built mainly through minor accretion are expected to be GeV-bright but comparatively TeV-faint because many clusters reside in lower-density outer halos. Quiescent systems show much weaker GC-related high-energy emission. These results suggest that gamma-rays can provide a novel probe of GC populations and, through them, of galaxy evolution itself. Moreover, they offer the advantage of being able to bypass dust obscuration in dense inner galactic regions where conventional tracers of GC systems are often incomplete. This opens a new route for connecting TeV observations of nearby galaxies to their fossil assembly histories.
