Astrophysicists link brightening of pulsar wind nebula to pulsar spin-down rate transition

Astrophysicists link brightening of pulsar wind nebula to pulsar spin-down rate transition
An illustration of the pulsar and pulsar wind nebula (PWN) system (not to scale). The relativistic wind from the central pulsar is terminated by a shock at a radius of about one light-year and starts to radiate. The typical size of a PWN is a few light-years. The image of the Large Magellanic Cloud galaxy shown in the lower left was taken by YE Ziyi . Credit: Institute of High Energy Physics

Astrophysicists have discovered that the pulsar wind nebula (PWN) surrounding the famous pulsar B0540-69 brightened gradually after the pulsar experienced a sudden spin-down rate transition (SRT). This discovery, made by a group of astrophysicists led by GE Mingyu and LU Fangjun at the Institute of High Energy Physics of the Chinese Academy of Sciences, provides important clues to the spin-down mechanism and the magnetic field structure of the pulsar, as well as the physical properties of the PWN. The results were published in Nature Astronomy.

Pulsars are highly magnetized neutron stars born from supernova explosions of massive stars. They typically have radii about 10 km and surface strengths around 1 trillion Gauss. According to classic theory, an isolated pulsar loses energy through magnetic dipole radiation and thus slows down. However, more and more theorists believe that the main way an isolated pulsar loses its rotational energy is through a relativistic wind consisting of electrons, positrons and possibly magnetic field. If the wind is strong enough, it will eventually form a detectable PWN through interaction with the surrounding materials. The famous Crab nebula is such a PWN, with a size of several light-years, i.e., about a hundred thousand times the distance from Earth to the Sun.

PSR B0540-69 is located in the Large Magellanic Cloud galaxy, a satellite galaxy about 160,000 light-years from our Milky Way. In December 2011, the spin-down rate of this pulsar suddenly increased by 36% and has remained almost constant since then, which means the energy release rate of the pulsar has also increased by 36%. Unlike other pulsars with similar spin-down rate transitions, which are accompanied by pulse profile and/or flux changes and are attributed to changes in the magnetospheres, no variation in either the pulse profile or flux has been detected from PSR B0540-69, making the cause of its SRT a mystery.

GE stated, "Using data obtained by a few X-ray astronomical satellites, we find that the X-ray PWN around PSR B0540-69 brightened gradually up to 32±8% over the prior flux during the period of about 400 days since the SRT. We show that the SRT most likely resulted from a sudden enhancement of the magnetic field in the pulsar magnetic pole region, which does not significantly affect the pulsed X-ray emission but increases pulsar wind power and hence PWN X-ray emission." This is the first time that PWN brightening has been observationally connected with the pulsar spin-down rate transition, implying that the pulsar wind is the main factor slowing down the pulsar spin. "The 400-day time scale of the flux increase corresponds to a magnetic field strength of about 0.8 milli-Gauss in the PWN. This is also the first direct measurement of the magnetic field and is consistent with the value estimated before under some assumptions," LU added.


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More information: The brightening of the pulsar wind nebula of PSR B0540−69 after its spin-down-rate transition, Nature Astronomy (2019). DOI: 10.1038/s41550-019-0853-5 , https://nature.com/articles/s41550-019-0853-5
Journal information: Nature Astronomy

Citation: Astrophysicists link brightening of pulsar wind nebula to pulsar spin-down rate transition (2019, August 26) retrieved 18 September 2019 from https://phys.org/news/2019-08-astrophysicists-link-brightening-pulsar-nebula.html
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Aug 26, 2019
The plasma ignoramuses just get so perplexed by electric discharge in plasmas.

Aug 27, 2019
With a magnetic field of 100million Tesla

Rotating with this pulsar
As cantdrive points out, plasma
A 100million Tesla field is going to have some pretty dramatic effects, electrically
In this rapidly spinning ball of compressed plasma
That
Jocelyn Bell Burnell, discovered and named a Pulsar
https://en.wikipe..._Burnell

As an aside, concerning Jocelyn Bell Burnell discovery, that pulsars spin
Pulsar B0540-69 spin-rate appears to be 20Hz?

Aug 27, 2019
The plasma ignoramuses just get so perplexed by electric discharge in plasmas.


And no one is more ignorant than you.

Aug 27, 2019
The plasma ignoramuses just get so perplexed by electric discharge in plasmas.


What a refreshing and original comment. Thank you!

Aug 27, 2019
Two Souls in Harmony

SCVGoodToGo, And no one is more ignorant than you
MrBojangles, What a refreshing and original comment. Thank you!

It must be how you tell them, SCVGoodToGo!

Aug 27, 2019
No, neutron stars are not made of plasma.


Aug 27, 2019
No, neutron stars are not made of plasma.
cantdrive hates neutron stars almost as much as he hates black holes... and math...

Aug 27, 2019
Neutron stars (and BH's) are but a fallacy proposed by morons and believed by those who are even stupider (see above comments) than the morons proposing the nonsensical pseudoscientific claptrap.

Aug 27, 2019
Da Schneib, these quarks are behaving as ionised plasma

Two Souls in Harmony

SCVGoodToGo, And no one is more ignorant than you
MrBojangles, What a refreshing and original comment. Thank you!

It must be how you tell them, SCVGoodToGo!

Da Schneib; No, neutron stars are not made of plasma

Foreth, Da Schneib believes in quarks
In this this Neutron
Apparently there are 2x -1/3 down quarks with 1x+2/3 up quark
As can be clearly seen
Although the charges neutrify
The quarks are in orbital's
The charges are unequally arranged
Where these quarks individually attract from outside, individual quarks
In a sense Da Schneib, these quarks are behaving as ionised plasma
Da Schneib, effectively making Neutrons plasma!

p.s. well, where there's magnetic- fields, electric fields are sure to travel

Aug 27, 2019
From the article:
They typically have radii about 10 km and surface magnetic field strengths around 1 trillion Gauss. According to classic pulsar theory, an isolated pulsar loses energy through magnetic dipole radiation and thus slows down. However, more and more theorists believe that the main way an isolated pulsar loses its rotational energy is through a relativistic wind consisting of electrons, positrons and possibly magnetic field.
I recall some years ago pointing out that the "Hulse-Taylor" Binary Pulsar System would be interacting so strongly (via their respective strong Magnetic Fields) that they would lose/radiate a lot of energy which would tighten/accelerate the binary system's MUTUAL ORBITAL PERIOD. I also pointed out that the previous attribution of this change in orbital period to 'gravitational wave losses' may need to be rethought to ALSO consider Magnetic Field Interaction for loss/period change rate. The above work/article should help towards that end. :)

Aug 27, 2019
The plasma ignoramuses just get so perplexed by electric discharge in plasmas.


And no one is more ignorant than you.
says SCVGoodToGo

Really now, was that necessary? This is a science website comment section, not an actual science lab. Stick to the science, ok?

Aug 27, 2019
Feel free to correct me if I'm wrong, but I think that it is Plasma that comprises the spaces BETWEEN Electrons and other Particles. The shape of Particles, Protons, Neutrons, and sub-particles are not square. They are all roundish, globular or elliptical. Which means that they are NOT flush up against each other with no spaces in between.
It is my contention that those spaces in between particles are filled with Plasma. The Plasma prevents too much friction between Particles, and allows them sliding motions/movements so that the Particles are able to join with others, or depart from them. Thus, odd number of Protons make up an Atom of one element, while an even number of Protons make up an Atom of another.

Aug 27, 2019
Additionally, those spaces between Particles that I believe to be filled with Plasma, MAY BE the MEDIUM in which electrical charges flow from one Particle to another.

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