Fermi Detects First Gamma-Ray Eclipses

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Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with NASA’s Universe of Learning partners: Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and NASA Jet Propulsion Laboratory.
Video imagery:

  • Animation of Fermi Gamma-ray Telescope: 
  • Gamma-ray orbital light curves of seven eclipsing spider pulsars, from paper “Gamma-ray orbital light curves of seven eclipsing spider pulsars.” Nature Astronomy. 26 January 2023.
  • Animation of eclipsing binary pulsar system: NASA/Sonoma State University, Aurore Simonnet

Writer: Leah Ramsay
Designer: Leah Hustak, Joseph Olmsted
Science review: Dr. Chris Britt
Education review: Jim Manning
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Collage of colorful space images, including nebulas, stars, planets, and galaxies. Text, News from the Universe. February 1, 2023. Fermi detects first gamma-ray eclipses. An animation of Fermi in space, orbiting Earth.
Text, Scientists have discovered the first gamma-ray eclipses using a decade of data from NASA's Fermi Gamma-Ray Space Telescope. Seven eclipsing binary star systems were detected that include a pulsar, the super-dense, rapidly rotating remains of a star that has gone supernova. An image shows seven waveform graphs, each one labeled "PSR" with a different letter and number combination next to it. The x axis on each graph is labeled Orbital Phase. Each graph has a red dotted line, with all the waves having one point that dips below the line. Text, When the companion star eclipses the pulsar, it blocks the pulsar's gamma-rays from reaching the telescope.
Illustration of an eclipse with a radiating pulsar next to it. Text, Scientists use the eclipses to measure the orbit tilt and mass of the pulsar, a key clue in understanding the extreme physics of the densest matter measurable.
This news was brought to you in part by NASA's Goddard Space Flight Center in Greenbelt, Maryland.