Millisecond pulsar in spin mode

Nov 03, 2011
Millisecond pulsar in spin mode
The NGC 6624 globular cluster in the Sagittarius constellation. The astronomers have identified a total of six pulsars in this globular cluster to date; the first one was J1823-3021A. Credit: Copyright NASA/ESA/I. King (University of California, Berkeley)

Astronomers have tracked down the first gamma-ray pulsar in a globular cluster of stars. It is around 27,000 light years away and thus also holds the distance record in this class of objects. Moreover, its high luminosity indicates that J1823-3021A is the youngest millisecond pulsar found to date, and that its magnetic field is much stronger than theoretically predicted. This therefore suggests the existence of a new population of such extreme objects. The discovery was made by Paulo Freire and an international team of scientists from the Max Planck Institute for Radio Astronomy in Bonn. The researchers evaluated data from the Fermi space telescope.

When the nuclear fuel in the core of a massive star is spent, the star collapses and releases so much energy in the process that it briefly radiates a billion times brighter than before. Such a supernova also marks the birth of a neutron star, an extremely compact with a diameter of around 20 kilometres but several million times the mass of the Earth. The neutron star spins very rapidly about its axis and accelerated; charged particles emit along the in different wavelength bands. This radiation is bundled along the magnetic field's axis - like the from a beacon.

Such a has rotational periods of between 16 milliseconds and eight seconds. The so-called millisecond pulsars, which have rotational periods down to 1.4 milliseconds, rotate even faster – this corresponds to 43,000 rotations per minute! It would seem that the initially lower rotational speed was subsequently increased as matter was accreted from a companion star. It is indeed the case that most of these millisecond pulsars can be found in binary star systems.

Millisecond pulsars have an extremely high rotational stability – even on long time scales; their cycle accuracy is comparable with that of the best atomic clocks on Earth. They are like huge flywheels in space, and hardly anything can affect their rotation. These objects can assist scientists to test the General Theory of Relativity; they can also be used in the search for gravitational waves and to analyse the properties of the superdense matter in the pulsar.

"We have now discovered more than 100 of these objects with radio telescopes," says Paulo Freire from the Institute for Radio Astronomy. "The high sensitivity of the Fermi telescope has now enabled us to track down a millisecond pulsar by its gamma radiation as well for the first time." The researchers found the pulsar with the designation J1823−3021A in the centre of a globular cluster.

Globular clusters are very old swarms of hundreds of thousands of stars whose gravitational forces bind them to each other. They are home to a large number of binary star systems that can lead to the formation of millisecond pulsars. One of these star clusters is NGC 6624 out towards the Sagittarius constellation. It is in the central region of our Milky Way, around 27,000 light years away. The researchers have been able to find a total of six pulsars in this globular cluster; J1823-3021A was the first.

With a rotational period of only 5.44 milliseconds (11,000 rotations per minute) it is also the most luminous pulsar detected to date in a globular cluster. J1823-3021A had already been discovered in the radio band back in 1994. Since then, regular time sequence measurements have been carried out with large radio telescopes, in particular with the Lovell telescope of the University of Manchester (Great Britain) and the Nançay telescope in France.

"We were very surprised to discover that the pulsar radiates very brightly in the gamma radiation band as well," says Damien Parent from the US Center for Earth Observing and Space Research. "We did not expect these millisecond pulsars to be so bright. This implies an unexpectedly strong magnetic field for such a rapidly rotating pulsar."

"This is a challenge for our current theories regarding the formation of such pulsars," explains Michael Kramer, Director at the Max Planck Institute in Bonn and head of the Fundamental Physics in research group there. "We are currently investigating a whole series of possible explanations. Nature might even be forming millisecond pulsars in a way that we do not even have on the radar as yet."

"No matter how these anomalous pulsars might form, one thing seems to be certain," says Paulo Freire: "In globular clusters, at least, these are objects so young that they are probably forming as often as the large number of normal which we already know about."

Explore further: Big black holes can block new stars

Related Stories

Astronomers get new tools for gravitational-wave detection

Jan 05, 2010

Teamwork between gamma-ray and radio astronomers has produced a breakthrough in finding natural cosmic tools needed to make the first direct detections of the long-elusive gravitational waves predicted by Albert Einstein ...

New technique improves estimates of pulsar ages

Jun 09, 2009

Astronomers at the University of California, Santa Cruz, have developed a new technique to determine the ages of millisecond pulsars, the fastest-spinning stars in the universe.

Fermi telescope unveils a dozen new pulsars

Jan 06, 2009

(PhysOrg.com) -- NASA's Fermi Gamma-ray Space Telescope has discovered 12 new gamma-ray-only pulsars and has detected gamma-ray pulses from 18 others. The finds are transforming our understanding of how these ...

9 new gamma pulsars

Nov 03, 2011

Pulsars are the lighthouses of the universe. These compact and fast-rotating neutron stars flash many times per second in the radio or gamma-ray band. Pure gamma-ray pulsars are extremely difficult to find ...

Recommended for you

Big black holes can block new stars

25 minutes ago

Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging galaxies, a study has found.

POLARBEAR seeks cosmic answers in microwave polarization

35 minutes ago

An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, ...

New radio telescope ready to probe

3 hours ago

Whirring back and forth on a turning turret, the white, 40-foot dish evokes the aura of movies such as "Golden Eye" or "Contact," but the University of Arizona team of scientists and engineers that commissioned ...

Exomoons Could Be Abundant Sources Of Habitability

Oct 20, 2014

With about 4,000 planet candidates from the Kepler Space Telescope data to analyze so far, astronomers are busy trying to figure out questions about habitability. What size planet could host life? How far ...

Partial solar eclipse over the U.S. on Thursday, Oct. 23

Oct 17, 2014

People in most of the continental United States will be in the shadow of the Moon on Thursday afternoon, Oct. 23, as a partial solar eclipse sweeps across the Earth. For people looking through sun-safe filters, from Los Angeles, ...

A newborn supernova every night

Oct 17, 2014

Thanks to a $9 million grant from the National Science Foundation and matching funds from the Zwicky Transient Facility (ZTF) collaboration, a new camera is being built at Caltech's Palomar Observatory that ...

User comments : 8

Adjust slider to filter visible comments by rank

Display comments: newest first

Star_Gazer
5 / 5 (1) Nov 03, 2011
Its amazing to see how it light would be bent by frame dragging of this massive object rotating that fast!
omatumr
1.3 / 5 (13) Nov 03, 2011
When the nuclear fuel in the core of a massive star is spent, the star collapses and releases so much energy in the process that it briefly radiates a billion times brighter than before. Such a supernova

a.) Marks the birth of a neutron star, or . . .


b.) Exposes the neutron star that was at the core of the star before it exploded?

That is the question!

See data and observations favoring choice b.)

"Neutron Repulsion", The
APEIRON Journal, in press (2011)
http://arxiv.org/...2.1499v1

With kind regards,
Oliver K. Manuel
http://myprofile....anuelo09
TimESimmons
1 / 5 (6) Nov 03, 2011
Pulsar kicks do not happen in globular clusters. Here's why:- http://www.presto...ndex.htm
Ethelred
4.1 / 5 (7) Nov 03, 2011
Oliver, since you missed these here they again.

You insist there is such a thing as neutron repulsion. You insist it is strong enough to stop the formation of black holes, not just stellar black holes but ALL black holes no matter what the size. Also it you claim it is long ranged enough to sunder galaxies. Though you refuse to answer any question about its actual strength or range those claims make it clear that it MUST be more powerful than gravity per unit of mass even if the mass is mostly hydrogen atoms as we can see makes up most the mass in the in the Universe, based on your denial of Dark Matter that is.

It really doesn't require a great deal of effort to notice that there is a severe problem with that set of claims. They make galaxies, stars, even neutron stars, planets and pretty much everything held together by gravity impossible.>>

Please explain this contradiction of reality that is an inevitable conclusion based on your own claims for Neutron Repulsion.

Ethelred
spaceagesoup
not rated yet Nov 04, 2011
uh oh, don't bring bark matter deniers into his kooky world.
Crazy_council
5 / 5 (2) Nov 04, 2011
is my maths right here, ( probebly not )

11,000 cycles per min = 183.33 cycles per second.

star is 20 miles in diamiter, thus 62 miles of surace area

11518 miles per second at the surface ?
antialias_physorg
5 / 5 (3) Nov 04, 2011
star is 20 miles in diamiter,

20 kilometers in diameter.

11518 miles per second at the surface ?

Depends on whether the entire thing rotates as one. We only observe the emission cone to rotate with those speeds - this does not tell us whether the thing is one rigid piece of matter or some bizarre neutron fluid.
If it were rigid then there would probably not be any gamma ray emissions as there would be no dynamo effect that could create a magnetic field (unless the whole thing is somehow magnetized or there is some effect due to infalling matter).

For the 5.4 millisecond pulsar I get a surface speed of 11500km per second

For the pulsar with 1.4 millisecond frequency mentioned in the article I get approx. 45000km per second
vidyunmaya
1 / 5 (5) Nov 05, 2011
At 27,000 Ly , this data from -J1823-3021A- provides a clear Index for time-Phase relationship- Magnetic field- Plasmas Interlinks that can be analyzed through-source-fields,Flows and Reflector concepts- now one can add Protective index to Plasma Regulated Electromagnetic Universe-1995-see Projections in my books-http://vidyardhic...pot.com/