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Discovered the pulsar farthest universe.

An international team of researchers, National Institute for Astrophysics (INAF), discovered a pulsar with extreme characteristics: it is the most distant and the brightest ever observed, and its existence will force scientists to rethink the theoretical models describing the operation of these heavenly bodies.
Pulsars are rapidly rotating neutron stars that emit beams of electromagnetic radiation: because of the great regularity of the rotation period, the emission of these beams appears to an external observer as a pulse at regular intervals.

NGC 5907 ULX, the pulsar discovery in this study – observed by telescopes X-ray Multi-Mirror Mission (XMM-Newton) and ESA’s Nuclear Spectroscopic Telescope Array (NuSTAR) NASA – is located in the spiral galaxy NGC 5907 and has very special properties….

First of all it is the most distant pulsar between those seen so far: its light takes 50 million years to reach Earth. Moreover, the pulsar is also brighter we know, so that manages to emit in a second the same amount of energy emitted by the sun in three and a half years.

Not only: the neutron star is increasing its mass at the expense of a companion star (a process known as accretion, which involves X-ray emission) at an astonishing rate. This is demonstrated by the significant change in the rotation period of the pulsar, which went from 1.43 to 1.13 seconds in the space of eleven years (in fact, the increase of the mass causes an acceleration in the rotation of the pulsar). It may seem like a small change, but it is not in percentage terms: to be clear, if we apply the same rate of change in the Earth’s rotation period, day length is shorten to five hours in the eleven years. But the real puzzle is to explain the extreme brightness of NGC 5907 ULX. So light sources (such ultraluminous X-ray sources) in theory may not be neutron stars, whose mass can not exceed 1.5 solar masses, but solid blacks holes, with extremely larger masses (between one hundred and one thousand times that of the Sun).

Based on current models, a pulsar with these features should not be observable, because it has a brightness of 1,000 times the maximum limit allowed for an object of this mass. This means that the accretion models that use should be reviewed. In the study, the authors have proposed a possible explanation, which involves the magnetic field of the pulsar.

My idea is that the magnetic field in the vicinity of the neutron star surface has a more complex configuration than has been considered so far: justify this assumption is the observed value of brightness is the fact that the material continues to increase.



To open the video click on the image, good view from your Alessandro Brizzi.