As a dazzling beacon in the dead of night, this powerful gamma radiation from the stellar envelope was seen in a nearby galaxy. The discovery made using the Fermi Space Gamma Telescope is the first gamma pulsar found outside the Milky Way. And this extragalactic object is a monster.
Pulsars are rapidly rotating neutron stars formed from the dense remnants of a once-massive star. After fuel production and then an explosion as supernova, depending on the initial mass of the star, the neutron star will represent the remainder of the rapidly rotating matter.
As expected, an extreme environment surrounds the pulsar. The magnetic field enveloping the young star, has the power of the original star, compressed into a ball the size of a couple of tens of miles. Such intense magnetism has powerful physics, emitting strong radiation from the poles of a rotating star. It is these rays of radiation that give the pulsar its name; as the neutron star rotates around its axis, rays of radiation pierce the sky, sometimes falling directly on Earth. We see these pulses as pulsating flashes - pulsars. Now, astronomers have found a pulsating, repeating signal in the center of the Tarantula Nebula, a nearby galaxy, the Large Magellanic Cloud, which is 163, 000 light-years away.
Since the Tarantula Nebula is an intense zinc formation, it is believed that known gamma emissions are generated by massive stars, which live and die young for a short time. If to explain in simple words, the more massive the star, the brighter it will burn its fuel and the faster it will explode like a supernova. Scientists assumed that this nebula is a place of birth and death of stars, and the flow of gamma rays is a by-product of stellar drama.
Astrophysicists believed that when supernova exploded in the Tarantula nebula, shock waves pass through the gases of the nebula. In this case, the particles are accelerated to high energies, generating cosmic rays (for example, high-energy protons). Interacting, cosmic waves form a powerful radiation or gamma rays.
Case is closed? Well, not quite.
Over the years, the Fermi Space Telescope collected data from the Large Magellanic Cloud, gradually forming a more detailed look at the Tarantula Nebula. Combining this data with new methods of analysis, astronomers made a rather startling discovery: the signals of two pulsars were found in the center and scientists believe that one of the pulsars, called J0540-6919, produces up to 60 percent of the gamma rays found in the nebula.
A type of gamma-same area shown above in the optical range. Lighter colors indicate a larger image of the gamma region in the optical range. Bright areas indicate a large amount of gamma rays with energies between 2 and 200 billion electron volts. For comparison, visible light varies between 2 and 3 electron volts. The two PSR J0540-6919 pulsars (left) and PSR J0537-6910 (right) clearly stand out in this image.
But astronomers have discovered not only the first ever gamma pulsar outside of our galaxy, they also found an object that is 20 times brighter than the most powerful known in our galaxy, which is located inside the Crab nebula and called PSR B0531 + 21 or just the Crab pulsar nebulae
This discovery made it possible to solve the mystery of a strange source of gamma radiation in the Tarantula nebula.
