Fermi finds the first extragalactic gamma-ray pulsar

Explore Fermi's discovery of the first gamma-ray pulsar detected in a galaxy other than our own.

Credit: NASA's Goddard Space Flight Center

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NASA's Fermi Gamma-ray Space Telescope has detected the first extragalactic gamma-ray pulsar, PSR J0540-6919, near the Tarantula Nebula (top center) star-forming region in the Large Magellanic Cloud, a satellite galaxy that orbits our own Milky Way. Fermi detects a second pulsar (right) as well but not its pulses. PSR J0540-6919 now holds the record as the highest-luminosity gamma-ray pulsar. The angular distance between the pulsars corresponds to about half the apparent size of a full moon. Background: An image of the Tarantula Nebula and its surroundings in visible light.

Credit: NASA's Goddard Space Flight Center; background: ESO/R. Fosbury (ST-ECF)

Unlabeled version of above.

A gamma-ray view of the same region shown above in visible wavelengths. Lighter colors indicate greater numbers of gamma rays with energies between 2 and 200 billion electron volts. For comparison, visible light ranges between 2 and 3 electron volts. The two pulsars, PSR J0540−6919 (left) and PSR J0537−6910, clearly stand out.

Credit: NASA/DOE/Fermi LAT Collaboration

The Tarantula Nebula (top center) is the largest, most active and most complex stellar nursery in our galactic neighborhood. It lies in the Large Magellanic Cloud, a satellite galaxy that orbits our own Milky Way about 163,000 light-years away. This image shows the Tarantula Nebula and its surroundings in a visible light image spanning one degree. The view is a mosaic captured with the Wide Field Imager on the 2.2-m telescope at the European Southern Observatory, La Silla, Chile.

Credit: ESO/R. Fosbury (ST-ECF)

Additional information and images

A gamma-ray view of the same region shown above in visible wavelengths. Lighter colors indicate greater numbers of gamma rays with energies between 2 and 200 billion electron volts. For comparison, visible light ranges between 2 and 3 electron volts. The two pulsars, PSR J0540−6919 (left) and PSR J0537−6910, clearly stand out.

Credit: NASA/DOE/Fermi LAT Collaboration

This image shows gamma-ray emission across a 10-degree-wide patch of the sky centered on the Large Magellanic Cloud. Lighter colors indicate greater numbers of gamma rays with energies between 0.2 and 200 billion electron volts (GeV). The brightest glow comes from the vicinity of the Tarantula Nebula star-forming region. Early in the Fermi mission, astronomers attributed this glow to collisions of subatomic particles accelerated in the shock waves produced by supernova explosions. However, much of it is now known to come from a single pulsar called PSR J0540-6919.

Credit: NASA/DOE/Fermi LAT Collaboration

This image shows gamma-ray emission across a 2-degree-wide patch of the sky centered on the Tarantula Nebula star-forming region in the Large Magellanic Cloud. Lighter colors indicate greater numbers of gamma rays with energies between 2 and 200 billion electron volts (GeV). Fermi's Large Area Telescope has better angular resolution at higher gamma-ray energies, allowing astronomers to resolve the broad glow of the Tarantula Nebula into two components coinciding with the pulsars PSR J0540−6919 and PSR J0537−6910.

Credit: NASA/DOE/Fermi LAT Collaboration