The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. We thank you in advance for your valuable feedback.
Fermi Gamma-ray Space Telescope
Fermi's Decade of Gamma-ray Discoveries
Fermi's Decade of Gamma-ray Discoveries

What is Fermi?

General Dynamics C4 Systems - Artist Concept of Fermi The Universe is home to numerous exotic and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. Supermassive black holes, merging neutron stars, streams of hot gas moving close to the speed of light ... these are but a few of the marvels that generate gamma-ray radiation, the most energetic form of radiation, billions of times more energetic than the type of light visible to our eyes. What is happening to produce this much energy? What happens to the surrounding environment near these phenomena? How will studying these energetic objects add to our understanding of the very nature of the Universe and how it behaves?

The Fermi Gamma-ray Space Telescope, formerly GLAST, is opening this high-energy world to exploration and helping us answer these questions. With Fermi, astronomers at long last have a superior tool to study how black holes, notorious for pulling matter in, can accelerate jets of gas outward at fantastic speeds. Physicists are able to study subatomic particles at energies far greater than those seen in ground-based particle accelerators. And cosmologists are gaining valuable information about the birth and early evolution of the Universe.

For this unique endeavor, one that brings together the astrophysics and particle physics communities, NASA has teamed up with the U.S. Department of Energy and institutions in France, Germany, Japan, Italy and Sweden. General Dynamics was chosen to build the spacecraft. Fermi was launched June 11, 2008 at 12:05 pm EDT.

Latest News

Nov 29, 2018

NASA's Fermi Traces the History of Starlight Across the Cosmos

Scientists using data from NASA's Fermi Gamma-ray Space Telescope have measured all the starlight produced over 90 percent of the universe's history. The analysis, which examines the gamma-ray output of distant galaxies, estimates the formation rate of stars and provides a reference for future missions that will explore the still-murky early days of stellar evolution.
+ Learn More

Nov 27, 2018

Pass 8 Data for the LAT Available

The FSSC is pleased to announce the availability of updated Pass 8 data for the LAT. These data files (P8R3) have a residual background that is significantly lower than the previous Pass 8 data (P8R2) and introduce a new event class, which is defined by a set of additional cuts on top of the SOURCE selection. See arXiv:1810.11394 for more details about the P8R3 data and LAT Data Products for more information. New IRFs and isotropic templates for use with the P8R3 data have been released with Fermitools 1.0.0.

Nov 1, 2018

GBM Team Releases GSpec 0.9.1

The Fermi Gamma-ray Burst Monitor Team is pleased to announce the release of GSpec 0.9.1, a first beta release for the Python replacement of RMfit, utilizing the community-standard XSPEC for spectral fitting. GSpec is built on top of the GBM Data Tools, which will be delivered with a full API in a future release. To download the package, please visit

» Full News Archive