The First Fermi-LAT Solar Flare Catalog

TL;DR

This paper presents the first comprehensive catalog of solar flares observed by Fermi-LAT, covering 2010-2018, with detailed gamma-ray data, including delayed emissions and behind-the-limb events, enabling new solar physics insights.

Contribution

It provides the largest sample of high-energy gamma-ray solar flares, including delayed and behind-the-limb emissions, facilitating population studies and advancing understanding of solar flare mechanisms.

Findings

45 gamma-ray solar flares detected with >5 sigma significance

37 flares exhibit delayed emission, 21 lasting over two hours

Gamma-ray spectra consistent with pion decay from >300 MeV protons

Abstract

We present the first Fermi - Large Area Telescope (LAT) solar flare catalog covering the 24 th solar cycle. This catalog contains 45 Fermi -LAT solar flares (FLSFs) with emission in the gamma-ray energy band (30 MeV - 10 GeV) detected with a significance greater than 5 sigma over the years 2010-2018. A subsample containing 37 of these flares exhibit delayed emission beyond the prompt-impulsive hard X-ray phase with 21 flares showing delayed emission lasting more than two hours. No prompt-impulsive emission is detected in four of these flares. We also present in this catalog the observations of GeV emission from 3 flares originating from Active Regions located behind the limb (BTL) of the visible solar disk. We report the light curves, spectra, best proton index and localization (when possible) for all the FLSFs. The gamma-ray spectra is consistent with the decay of pions produced by >300 MeV protons. This work contains the largest sample of high-energy gamma-ray flares ever reported and provides the unique opportunity to perform population studies on the different phases of the flare and thus allowing to open a new window in solar physics.