NASA’s Fermi Satellite Finds Gamma-Ray Pulsar In Tarantula Nebular, Another Galaxy

Posted: Nov 13 2015, 6:07am CST | by , in News | Latest Science News


Gamma-ray pulsar
Photo credit: NASA's Goddard Space Flight Center; background: ESO/R. Fosbury (ST-ECF)

Taking advantage of NASA’s Fermi Gamma-ray Space Telescope, researchers have been able to detect gamma-ray pulsar in the Tarantula Nebula of the Large Magellanic Cloud – another galaxy different from ours. This is the first time gamma-rays would be found outside of our galaxy, and the new discovery presents the most luminous gamma-ray pulsar ever known to scientists.

The Tarantula Nebula is situated in another small galaxy orbiting our Milky Way and it is at a distance of 163,000 light-years away. This is the biggest and most active region forming stars in our galactic outskirts. It produces strong gamma-rays, the highest form of light energy.

When the Fermi mission just started, researchers thought the glow was due to the merging of subatomic particles quickened in shock waves generated by supernova explosions.

"It's now clear that a single pulsar, PSR J0540-6919, is responsible for roughly half of the gamma-ray brightness we originally thought came from the nebula," said lead scientist Pierrick Martin, an astrophysicist at the National Center for Scientific Research (CNRS) and the Research Institute in Astrophysics and Planetology in Toulouse, France. "That is a genuine surprise."

The explosion of a massive star produces what is known as supernova, and this phenomenon may preserve the core of the star from destruction, forming a neutron star, a situation where the mass of over 500,000 Earths is crumpled into a magnetized ball. This causes an disengaged neutron star to spin several times per second, generating magnetic field that powers beams of radio waves, x-rays, gamma rays, and visible light in space. Astronomers can see the pulse of emission as the beam sweeps past Earth, producing what is known as pulsar.

The two pulsars PSR J0540-6919 (or J0540) and PSR J0537−6910 (J0537) are known to inhabit the Tarantula Nebula, and these were detected with NASA’s Einstein and Rossi X-ray Timing Explorer satellites. However, Fermi’s Large Area Telescope (LAT) spent over six years monitoring J0540 among others.

"The gamma-ray pulses from J0540 have 20 times the intensity of the previous record-holder, the pulsar in the famous Crab Nebula, yet they have roughly similar levels of radio, optical and X-ray emission," said co-author Lucas Guillemot, at the Laboratory for Physics and Chemistry of Environment and Space, operated by CNRS and the University of Orléans in France. "Accounting for these differences will guide us to a better understanding of the extreme physics at work in young pulsars."

J0540 is estimated to be around 1,700 years old, nearly double that of the Crab Nebula pulsar. And then, almost all the 2,500 presently identified pulsars are aged between 10,000 to hundreds of millions of years old.

"This campaign began as a search for a pulsar created by SN 1987A, the closest supernova seen since the invention of the telescope," said co-author Francis Marshall, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "That search failed, but it discovered J0537."

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States. It has found over 160 gamma-ray pulsars since its launch in 2008, as against the seven known before its deployment.

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The Author

<a href="/latest_stories/all/all/52" rel="author">Charles I. Omedo</a>
Charles is covering the latest discoveries in science and health as well as new developments in technology. He is the Chief Editor or Intel-News.




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