Fermi's Large Area Telescope (LAT) scans the entire sky every three hours, continually deepening its portrait of the sky in gamma rays, the most extreme form of light. While the energy of visible light falls between about 2 and 3 electron volts, the LAT detects gamma rays with energies ranging from 20 million electron volts (MeV) to more than 300 billion (GeV).
But at higher energies, gamma rays are few and far between. Above 10 GeV, even Fermi's LAT detects only one gamma ray every four months from some sources. The LAT's predecessor, the EGRET instrument on NASA's Compton Gamma Ray Observatory, detected only 1,500 individual gamma rays in this range during its nine-year lifetime, while the LAT detected more than 150,000 in just three years.
Any object producing gamma rays at these energies is undergoing extraordinary astrophysical processes. More than half of the 496 sources in the new census are active galaxies, where matter falling into a supermassive black hole powers jets that spray out particles at nearly the speed of light.", "items": [], "extra_data": {} }, { "id": 350276, "url": "https://svs.gsfc.nasa.gov/10887/#media_group_350276", "widget": "Single image", "title": "", "caption": "", "description": "Fermi's view of the gamma-ray sky continually improves. This image of the entire sky includes three years of observations by Fermi's Large Area Telescope (LAT). It shows how the sky appears at energies greater than 1 billion electron volts (1 GeV). Brighter colors indicate brighter gamma-ray sources. A diffuse glow fills the sky and is brightest along the plane of our galaxy (middle). Discrete gamma-ray sources include pulsars and supernova remnants within our galaxy as well as distant galaxies powered by supermassive black holes.
Credit: NASA/DOE/Fermi LAT Collaboration", "items": [ { "id": 324869, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480105, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/Fermi-3-year.jpg", "filename": "Fermi-3-year.jpg", "media_type": "Image", "alt_text": "Fermi's view of the gamma-ray sky continually improves. This image of the entire sky includes three years of observations by Fermi's Large Area Telescope (LAT). It shows how the sky appears at energies greater than 1 billion electron volts (1 GeV). Brighter colors indicate brighter gamma-ray sources. A diffuse glow fills the sky and is brightest along the plane of our galaxy (middle). Discrete gamma-ray sources include pulsars and supernova remnants within our galaxy as well as distant galaxies powered by supermassive black holes. 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Credit: NASA/DOE/Fermi LAT Collaboration", "width": 80, "height": 40, "pixels": 3200 } }, { "id": 324873, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480108, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/Fermi-3-year_searchweb.png", "filename": "Fermi-3-year_searchweb.png", "media_type": "Image", "alt_text": "Fermi's view of the gamma-ray sky continually improves. This image of the entire sky includes three years of observations by Fermi's Large Area Telescope (LAT). It shows how the sky appears at energies greater than 1 billion electron volts (1 GeV). Brighter colors indicate brighter gamma-ray sources. A diffuse glow fills the sky and is brightest along the plane of our galaxy (middle). Discrete gamma-ray sources include pulsars and supernova remnants within our galaxy as well as distant galaxies powered by supermassive black holes. 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Credit: NASA/DOE/Fermi LAT Collaboration", "items": [ { "id": 324875, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480110, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/Fermi_10_Gev.jpg", "filename": "Fermi_10_Gev.jpg", "media_type": "Image", "alt_text": "This all-sky Fermi view includes only sources with energies greater than 10 GeV. From some of these sources, Fermi's LAT detects only one gamma-ray photon every four months. Brighter colors indicate brighter gamma-ray sources. Credit: NASA/DOE/Fermi LAT Collaboration", "width": 6973, "height": 4000, "pixels": 27892000 } }, { "id": 324876, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480111, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/Fermi_10_Gev_web.png", "filename": "Fermi_10_Gev_web.png", "media_type": "Image", "alt_text": "This all-sky Fermi view includes only sources with energies greater than 10 GeV. From some of these sources, Fermi's LAT detects only one gamma-ray photon every four months. Brighter colors indicate brighter gamma-ray sources. Credit: NASA/DOE/Fermi LAT Collaboration", "width": 320, "height": 183, "pixels": 58560 } }, { "id": 324874, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480109, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/Fermi_10_Gev.tif", "filename": "Fermi_10_Gev.tif", "media_type": "Image", "alt_text": "This all-sky Fermi view includes only sources with energies greater than 10 GeV. From some of these sources, Fermi's LAT detects only one gamma-ray photon every four months. Brighter colors indicate brighter gamma-ray sources. Credit: NASA/DOE/Fermi LAT Collaboration", "width": 6973, "height": 4000, "pixels": 27892000 } } ], "extra_data": {} }, { "id": 350278, "url": "https://svs.gsfc.nasa.gov/10887/#media_group_350278", "widget": "Single image", "title": "", "caption": "", "description": "New sources emerge and old sources fade as the LAT's view extends into higher energies.
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Neronov et al.", "width": 320, "height": 157, "pixels": 50240 } } ], "extra_data": {} }, { "id": 350279, "url": "https://svs.gsfc.nasa.gov/10887/#media_group_350279", "widget": "Single image", "title": "", "caption": "", "description": "More than half of the sources above 10 GeV are black-hole-powered active galaxies. More than a third of the sources are completely unknown, having no identified counterpart detected in other parts of the spectrum.", "items": [ { "id": 324879, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 480114, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010887/10_Gev_graph.jpg", "filename": "10_Gev_graph.jpg", "media_type": "Image", "alt_text": "More than half of the sources above 10 GeV are black-hole-powered active galaxies. 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The most prominent feature is the bright, diffuse glow running along the middle of the map, which marks the central plane of our Milky Way galaxy. The gamma rays there are mostly produced when energetic particles accelerated in the shock waves of supernova remnants collide with gas atoms and even light between the stars. Many of the star-like features above and below the Milky Way plane are distant galaxies powered by supermassive black holes. Many of the bright sources along the plane are pulsars. The image was constructed from 12 years of observations using front-converting gamma rays with energies greater than 1 GeV. Hammer projection.Credit: NASA/DOE/Fermi LAT Collaboration || Fermi_144-month_Fermi_all-sky_hammer_2160x1080.png (2160x1080) [2.4 MB] || Fermi_144-month_Fermi_all-sky_hammer_2160x1080_print.jpg (1024x512) [306.6 KB] || Fermi_144-month_Fermi_all-sky_hammer_4000x2000.png (4000x2000) [7.0 MB] || Fermi_144-month_Fermi_all-sky_hammer_3600x1800.png (3600x1800) [4.9 MB] || ", "release_date": "2022-02-12T00:00:00-05:00", "update_date": "2022-02-07T14:45:20-05:00", "main_image": { "id": 373454, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a014000/a014090/Fermi_144_month_all-sky-cyl_3600x1800_print.jpg", "filename": "Fermi_144_month_all-sky-cyl_3600x1800_print.jpg", "media_type": "Image", "alt_text": "Same as above but in the equidistant cylindrical projection.Credit: NASA/DOE/Fermi LAT Collaboration", "width": 1024, "height": 512, "pixels": 524288 } }, { "id": 11342, "url": "https://svs.gsfc.nasa.gov/11342/", "page_type": "Produced Video", "title": "Fermi's Five-year View of the Gamma-ray Sky", "description": "This all-sky view shows how the sky appears at energies greater than 1 billion electron volts (GeV) according to five years of data from NASA's Fermi Gamma-ray Space Telescope. (For comparison, the energy of visible light is between 2 and 3 electron volts.) The image contains 60 months of data from Fermi's Large Area Telescope; for better angular resolution, the map shows only gamma rays converted at the front of the instrument's tracker. Brighter colors indicate brighter gamma-ray sources. The map is shown in galactic coordinates, which places the midplane of our galaxy along the center. The five-year Fermi map is available in multiple resolutions below, along with additional plots containing reference information and identifying some of the brightest sources. || ", "release_date": "2013-08-21T13:00:00-04:00", "update_date": "2021-09-10T15:10:50-04:00", "main_image": { "id": 462843, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011300/a011342/Femri_5_year_11000x6189_web.jpg", "filename": "Femri_5_year_11000x6189_web.jpg", "media_type": "Image", "alt_text": "The Fermi LAT 60-month image, constructed from front-converting gamma rays with energies greater than 1 GeV. The most prominent feature is the bright band of diffuse glow along the map's center, which marks the central plane of our Milky Way galaxy. The gamma rays are mostly produced when energetic particles accelerated in the shock waves of supernova remnants collide with gas atoms and even light between the stars. Hammer projection. Image credit: NASA/DOE/Fermi LAT Collaboration", "width": 320, "height": 180, "pixels": 57600 } } ], "sources": [], "products": [], "newer_versions": [], "older_versions": [], "alternate_versions": [] }