{ "id": 11437, "url": "https://svs.gsfc.nasa.gov/11437/", "page_type": "Produced Video", "title": "First Gamma-ray Measurement of a Gravitational Lens", "description": "Astronomers using NASA's Fermi observatory have made the first gamma-ray measurements of a gravitational lens, a kind of natural telescope formed when a rare cosmic alignment allows the gravity of a massive object to bend and amplify light from a more distant source.The opportunity arose in September 2012, when Fermi's Large Area Telescope (LAT) detected a series of bright gamma-ray flares from a source known as B0218+357, located 4.35 billion light-years away in the constellation Triangulum. These powerful outbursts in a known gravitational lens provided the key to making the measurement. Astronomers classify B0218+357 as a blazar, a type of active galaxy noted for intense outbursts. At the blazar's heart is a supersized black hole with a mass millions to billions of times that of the sun. As matter spirals toward this black hole, some of it blasts outward as jets of particles traveling near the speed of light in opposite directions.Long before light from B0218+357 reaches us, it passes directly through a spiral galaxy – one much like our own – located 4.03 billion light-years away. The galaxy's gravity bends the light into different paths, so astronomers see the background blazar as dual images. But these paths aren't the same length, which means that when one image flares, there's a delay of many days before the other does.While radio and optical telescopes can resolve and monitor the individual blazar images, Fermi's LAT cannot. Instead, the Fermi team exploited the playback delay between the images. In September 2012, when the blazar's flaring activity made it the brightest gamma-ray source outside of our own galaxy, Fermi scientists took advantage of the opportunity by using a week of dedicated LAT time to hunt for delayed flares. Three episodes of flares showing playback delays of 11.46 days were found, with the strongest evidence in a sequence of flares captured during the week-long LAT observations. || ", "release_date": "2014-01-06T10:00:00-05:00", "update_date": "2023-05-03T13:51:19.955910-04:00", "main_image": { "id": 459769, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/Lensed_Blazar_Still.jpg", "filename": "Lensed_Blazar_Still.jpg", "media_type": "Image", "alt_text": "This movie illustrates the components of a gravitational lens system known as B0218+357. Different sight lines to a background blazar result in two images that show outbursts at slightly different times. NASA's Fermi made the first gamma-ray measurements of this delay in a lens system. Credit: NASA's Goddard Space Flight Center", "width": 1920, "height": 1080, "pixels": 2073600 }, "main_video": { "id": 459770, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/11437_Lensed_Blazar_Final_H264_1280x720_30.mov", "filename": "11437_Lensed_Blazar_Final_H264_1280x720_30.mov", "media_type": "Movie", "alt_text": "This movie illustrates the components of a gravitational lens system known as B0218+357. Different sight lines to a background blazar result in two images that show outbursts at slightly different times. NASA's Fermi made the first gamma-ray measurements of this delay in a lens system. Credit: NASA's Goddard Space Flight Center", "width": 1280, "height": 720, "pixels": 921600 }, "main_credits": { "Visualizations by": [ { "name": "Scott Wiessinger", "employer": "USRA" } ] }, "progress": "Complete", "media_groups": [ { "id": 342061, "url": "https://svs.gsfc.nasa.gov/11437/#media_group_342061", "widget": "Basic text with HTML", "title": "", "caption": "", "description": "Astronomers using NASA's Fermi observatory have made the first gamma-ray measurements of a gravitational lens, a kind of natural telescope formed when a rare cosmic alignment allows the gravity of a massive object to bend and amplify light from a more distant source.

The opportunity arose in September 2012, when Fermi's Large Area Telescope (LAT) detected a series of bright gamma-ray flares from a source known as B0218+357, located 4.35 billion light-years away in the constellation Triangulum. These powerful outbursts in a known gravitational lens provided the key to making the measurement.

Astronomers classify B0218+357 as a blazar, a type of active galaxy noted for intense outbursts. At the blazar's heart is a supersized black hole with a mass millions to billions of times that of the sun. As matter spirals toward this black hole, some of it blasts outward as jets of particles traveling near the speed of light in opposite directions.

Long before light from B0218+357 reaches us, it passes directly through a spiral galaxy – one much like our own – located 4.03 billion light-years away. The galaxy's gravity bends the light into different paths, so astronomers see the background blazar as dual images. But these paths aren't the same length, which means that when one image flares, there's a delay of many days before the other does.

While radio and optical telescopes can resolve and monitor the individual blazar images, Fermi's LAT cannot. Instead, the Fermi team exploited the playback delay between the images.

In September 2012, when the blazar's flaring activity made it the brightest gamma-ray source outside of our own galaxy, Fermi scientists took advantage of the opportunity by using a week of dedicated LAT time to hunt for delayed flares.

Three episodes of flares showing playback delays of 11.46 days were found, with the strongest evidence in a sequence of flares captured during the week-long LAT observations.", "items": [], "extra_data": {} }, { "id": 342062, "url": "https://svs.gsfc.nasa.gov/11437/#media_group_342062", "widget": "Video player", "title": "", "caption": "", "description": "This movie illustrates the components of a gravitational lens system known as B0218+357. Different sight lines to a background blazar result in two images that show outbursts at slightly different times. NASA's Fermi made the first gamma-ray measurements of this delay in a lens system.

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Credit: NASA's Goddard Space Flight Center", "items": [ { "id": 295821, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 459791, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/Lensed_Blazar_Still_plain.jpg", "filename": "Lensed_Blazar_Still_plain.jpg", "media_type": "Image", "alt_text": "Print resolution still of gravitational lens system illustration. No labels or light paths.Credit: NASA's Goddard Space Flight Center", "width": 3840, "height": 2160, "pixels": 8294400 } }, { "id": 295823, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 459793, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/Lensed_Blazar_Still_plain_web.png", "filename": "Lensed_Blazar_Still_plain_web.png", "media_type": "Image", "alt_text": "Print resolution still of gravitational lens system illustration. No labels or light paths.Credit: NASA's Goddard Space Flight Center", "width": 320, "height": 180, "pixels": 57600 } }, { "id": 295822, "type": "media", "extra_data": null, "title": null, "caption": null, "instance": { "id": 459792, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/Lensed_Blazar_Still_plain.tif", "filename": "Lensed_Blazar_Still_plain.tif", "media_type": "Image", "alt_text": "Print resolution still of gravitational lens system illustration. No labels or light paths.Credit: NASA's Goddard Space Flight Center", "width": 3840, "height": 2160, "pixels": 8294400 } } ], "extra_data": {} }, { "id": 342067, "url": "https://svs.gsfc.nasa.gov/11437/#media_group_342067", "widget": "Basic text", "title": "For More Information", "caption": "", "description": "See [http://www.nasa.gov/press/2014/january/nasas-fermi-makes-first-gamma-ray-study-of-a-gravitational-lens/](http://www.nasa.gov/press/2014/january/nasas-fermi-makes-first-gamma-ray-study-of-a-gravitational-lens/)", "items": [], "extra_data": {} } ], "studio": "gms", "funding_sources": [ "NASA Astrophysics" ], "credits": [ { "role": "Animator", "people": [ { "name": "Scott Wiessinger", "employer": "USRA" } ] }, { "role": "Producer", "people": [ { "name": "Scott Wiessinger", "employer": "USRA" } ] }, { "role": "Writer", "people": [ { "name": "Francis Reddy", "employer": "Syneren Technologies" } ] } ], "missions": [ "Fermi Gamma-ray Space Telescope" ], "series": [ "Astrophysics Animations", "Astrophysics Stills" ], "tapes": [], "papers": [ "http://arxiv.org/abs/1401.0548", "http://arxiv.org/abs/1401.0548" ], "datasets": [], "nasa_science_categories": [ "Universe" ], "keywords": [ "Ast", "Astrophysics", "Black Hole", "Blazar", "Earth Science", "Fermi", "Galaxy", "Gamma Ray", "Gravity", "HDTV", "Hubble Space Telescope", "Space", "Spectral/Engineering", "Universe" ], "recommended_pages": [], "related": [ { "id": 10819, "url": "https://svs.gsfc.nasa.gov/10819/", "page_type": "Produced Video", "title": "Fermi's Latest Gamma-ray Census Highlights Cosmic Mysteries", "description": "Every three hours, NASA's Fermi Gamma-ray Space Telescope scans the entire sky and deepens its portrait of the high-energy universe. Every year, the satellite's scientists reanalyze all of the data it has collected, exploiting updated analysis methods to tease out new sources. These relatively steady sources are in addition to the numerous transient events Fermi detects, such as gamma-ray bursts in the distant universe and flares from the sun.Earlier this year, the Fermi team released its second catalog of sources detected by the satellite's Large Area Telescope (LAT), producing an inventory of 1,873 objects shining with the highest-energy form of light. More than half of these sources are active galaxies whose supermassive black hole centers are causing the gamma-ray emissions. || ", "release_date": "2011-09-09T09:00:00-04:00", "update_date": "2023-05-03T13:53:38.663881-04:00", "main_image": { "id": 483805, "url": "https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010819/Blazar_Still_2.jpg", "filename": "Blazar_Still_2.jpg", "media_type": "Image", "alt_text": "Active galaxies called blazars make up the largest class of objects detected by Fermi's Large Area Telescope (LAT). Massive black holes in the hearts of these galaxies fire particle jets in our direction. Fermi team member Elizabeth Hays narrates this quick tour of blazars, which includes LAT movies showing how rapidly their emissions can change. Credit: NASA/Goddard Space Flight Center/CI LabWatch this video on the NASAexplorer YouTube channel.For complete transcript, click here.", "width": 1280, "height": 720, "pixels": 921600 } } ], "sources": [], "products": [], "newer_versions": [], "older_versions": [], "alternate_versions": [] }