Fermi Solar Flare X-Ray and Gamma-Ray Observations

The Fermi Gamma-ray Space Telescope was launched in June 2008 to explore high-energy phenomena in the Universe.  This GI program is targeted specifically at Fermi observations of high-energy solar phenomena, primarily solar flares.  We provide quicklook products, data archives, and analysis software covering the solar X-ray and gamma-ray observations of both the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT), with the objective of facilitating and encouraging the broad use of Fermi data by the international solar physics community.

Summary of GBM and LAT Data

What we provide:

GBM Solar Flare List Autonomous flare finder identifies all flares ≥ GOES C-Class detected by GBM above 10 keV.  (FITS file)
LAT Significant Event List Time periods when the >100 MeV fluxes computed via the light-bucket method deviate significantly from the mean level during a 4-day period.
GBM Quicklook Daily and Orbital Plots Time histories of NaI, GBO, and GOES data, with flare and day/night markers. Orbital plots are on RHESSI orbit times. 

Direct Links to PNG files:   Daily Plots   Orbit Plots

GBM Response Matrix FITS Files Time-dependent detector response matrices for each GBM detector covering the duration of every GBM flare.  Needed in the spectral analysis software to relate observed count-rate spectra to model photon spectra. Suitable for analyzing CPEC and CTIME data.
LAT 4-day Quicklook Plots
LAT solar gamma-ray flux > 100 MeV, one point per solar exposure (i.e. average of the 20-40 minutes of solar observation every ~1.5 hours) calculated by two different methods.

Direct Link to PNG files: Light-Bucket plots  or Maximum Likelihood plots
Explanation of LAT quicklook plot methods

LAT Daily Lightcurve FITS Files LAT data between 100 MeV and 10 GeV filtered for solar counts in 1-minute time bins, no energy binning, using light-bucket method.  Contains exposure (cm^2 s) information.
LAT Daily Spectrum FITS Files LAT data filtered for solar counts in 1-minute time bins, 10 energy bins from 30 MeV to 10 GeV, usnig light-bucket method.  Used as the basis for the LAT quicklook plots, and as input to the OSPEX spectral analysis software.
LAT Response Matrix FITS Files LAT detector response matrices for each solar exposure period (20-40 minutes every ~1.5 hours).
GBM Spectral Analysis

LAT Spectral Analysis

OSPEX, IDL spectral analysis software package, is used to
  • view count-rate data as a function of time or energy
  • convert count-rate spectra to incident photon spectra using various selectable functions.

For GBM, input is daily or trigger CSPEC or CTIME file from Fermi archive and corresponding response file from our archive.  For LAT, input is daily spectrum file and corresponding response file, both from our archive.

See the OSPEX Guide for more information.

IDL Utility Routines Useful SSW IDL routines for Fermi solar data analysis.


List of refereed publications using Fermi solar observations

Proposal, Reports, and Presentations for this project:

Solar Links:


Fermi Links:



This project is funded by the Fermi GI program.

Please include the following acknowledgement if you use these facilities in a paper or presentation:
"We acknowledge the use of the Fermi Solar Flare Observations facility funded by the Fermi GI program (https://hesperia.gsfc.nasa.gov/fermi_solar/)."

Last updated 31 January, 2018 by Kim Tolbert