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.
We are pleased to announce that the Large Area Telescope Collaboration has released the third catalog of gamma-ray pulsars (3PC) using as much as 14 years of data. The catalog reports 340 gamma-ray pulsars and candidates, including 294 gamma-ray pulsars found in the LAT data; 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources; and a dozen optical and/or X-ray binary systems co-located with LAT sources that likely harbor gamma-ray MSPs. The electronic catalog version provides gamma-ray pulsar ephemerides, properties and fit results to guide and be compared with modeling results. An all-sky gamma-ray sensitivity map is provided for population synthesis studies. Photon data files are provided for the gamma-ray pulsars that include phase and model weights. The 3PC Catalog data products are available online, where you can find individual summary pages for the gamma-ray pulsars. The construction and details of the catalog are described in the 3PC paper. You can also find the 3PC pulsars as an overlay option for the Fermi LAT Light Curve Repository (LCR). Scroll down to "Data Overlays" at the left and slide the 3PC button to "on". The 3PC will now appear as a tab under "Catalog Sources". Clicking on one of the Source IDs in the table will take you to the individual pulsar summary page.
We are pleased to announce that the Large Area Telescope Collaboration has released 4FGL-DR4, an incremental version of the fourth full catalog of LAT sources, based on 14 years of survey data in the 50 MeV-1 TeV energy range. In this fourth data release, the number of sources increased from 6658 in 4FGL-DR3 with 12 years of data to 7194 in 4FGL-DR4 with 14 years of data. The DR4 analysis is similar to that used in DR3 and is described in the DR3 paper. The spectral parameters, spectral energy distributions, light curves and associations are updated for all sources. See the DR4 document and the 4FGL paper for the full details.
Due to a temporary misconfiguration of the LAT while implementing routine updates to the tracker hot strip mask, there was a 1.75-hour loss of data on 18 July 2023 from 18:04 to 19:50 UTC. The configuration was quickly reverted and normal data taking was restored. A further inconsistency of the configuration with the ground pipeline has delayed processing of data acquired from 18 July 2023 19:50 UTC to 19 July 2023 17:31 UTC. These data will become available after manual reprocessing. Nominal data taking and automated processing resumed 19 July 2023 17:31 UTC.