Searching for sub-populations within the gamma-ray solar flares catalog: a graph-based clustering analysis

Abstract

Solar flares are highly energetic events that happen in the solar atmosphere. They are mostly observed as X-ray or gamma-ray bursts located on the Sun's surface. While they are known to be sites of particle acceleration, the acceleration process(es) responsible for the observed fluxes remain unsure. The diversity in shape and duration of the gamma-ray fluxes suggests the existence of distinct phases of hadronic acceleration. Moreover, different acceleration processes could explain the differences observed among flares. In this work we search for the evidence of sub-populations within the catalog of gamma-ray solar flares observed by Fermi-LAT. We aim at grouping flares with similar physical properties to be able to probe theoretical models for neutrino production within different classes of flares. We use measurements of the X-ray and gamma-ray fluxes, as well as CMEs and SEPs, to cluster the events using a graph-based algorithm. Furthermore, we investigate the most representative features that characterise the identified sub-populations to allow for qualitative analysis and model development.