Scientists detect unexpected drop in the magnetic field of an X-ray pulsar

pulsar
The pulsar pictured here, which resides in the Messier 82 galaxy 12 million light-years away, sends out X-ray beams that pass Earth every 1.37 seconds. Scientists studying this object with NuSTAR originally thought it was a massive black hole, but its X-ray pulse revealed its true pulsar identity. Credit: NASA/JPL-Caltech

(Phys.org)—A team of scientists has recently presented evidence of an unexpected drop in the observed magnetic field of an accreting pulsar designated V0332+53. This downturn, observed after the pulsar underwent a bright, three-month-long X-ray outburst, could yield important information on how the accreted mass settling on the surface of a neutron star affects its magnetic field. The findings are detailed in a paper published online on Apr. 26 in the arXiv journal.

V0332+53 is an accreting pulsar emitting X-ray radiation, with a spin period of 4.4 seconds. It orbits an early type companion star in an eccentric orbit of about 34 days. Significantly, this pulsar shows sporadic giant X-ray outbursts lasting several weeks, followed by years-long intervals of dormancy.

These X-ray outburst were observed in 1989, between November 2004 and February 2005, and between June and September 2015. The latest outburst drew the attention of a team of researchers, led by Giancarlo Cusumano of the Institute of Space Astrophysics and Cosmic Physics in Palermo, Italy. Using the Burst Alert Telescope (BAT) and the X-Ray Telescope (XRT), both mounted on NASA's Swift spacecraft, the astronomers were able to observe the pulsar in soft X-ray and high-energy bands.

By studying the results, the team detected a noteworthy drop in the observed magnetic field between the onset and the end of the outburst.

"The comparison of the XRT profiles in the soft X-rays provides a hint against the hypothesis of a geometrical beam variation. If, on the other hand, the line-forming region is the same at equal luminosities, the observed difference in the cyclotron energy corresponds to a difference in the magnetic field of about 1.7 ×1011 G," the researchers wrote in the paper.

The findings could be crucial for our understanding of matter accretion processes in and could provide new insights on pulsars' X-ray outburst events. According to the research, the magnetic field of neutron star drives the accreting matter along its field lines towards the magnetic polar caps, forming an accretion column, where matter is followed up by radiative processes that produce X-rays.

Notably, the drop in the magnetic field, as described in the latest paper, wasn't observed after previous outbursts. The researchers found out that although the total mass accreted at the end of the 2004-2005 and the 2015 outburst is similar, during the 2004-2005 event, a higher luminosity was reached earlier. They also concluded that decay of the magnetic field is not directly proportional to the total accreted mass.

Moreover, the scientists hypothesize that the cause of the significant decay of the through accretion observed at V0332+53could be due to "diamagnetic screening."

"In this hypothesis, the accreting plasma builds up to form a magnetically confined mound, where the gas pressure balances the magnetic stresses. This would produce, as an overall effect, a distortion of the field lines observed as a decrease of the field component along the accretion column," the paper reads.

However, as the team noted, the lack of coverage in the first ten days of the outburst doesn't allow them to confirm this theory.


Explore further

A magnetic monster's dual personality

More information: Topic Model Based Multi-Label Classification from the Crowd, arXiv:1604.00783 [cs.LG] arxiv.org/abs/1604.0783

Abstract
Multi-label classification is a common supervised machine learning problem where each instance is associated with multiple classes. The key challenge in this problem is learning the correlations between the classes. An additional challenge arises when the labels of the training instances are provided by noisy, heterogeneous crowdworkers with unknown qualities. We first assume labels from a perfect source and propose a novel topic model where the present as well as the absent classes generate the latent topics and hence the words. We non-trivially extend our topic model to the scenario where the labels are provided by noisy crowdworkers. Extensive experimentation on real world datasets reveals the superior performance of the proposed model. The proposed model learns the qualities of the annotators as well, even with minimal training data.

Journal information: arXiv

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May 05, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.

May 05, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.


Perhaps you could link to the EU modelling for x-ray pulsars, to show us how they weren't surprised. Or have they never done any, and just want to snipe at the fringes, as usual, despite never having contributed jack s**t to the field of astrophysics?

May 05, 2016
the arxiv reference is clearly wrong. I tried a search "Giancarlo Cusumano" but I didn't find anything published in april.

May 05, 2016
the arxiv reference is clearly wrong. I tried a search "Giancarlo Cusumano" but I didn't find anything published in april.


You need the one from further up, where it says "more information".
https://arxiv.org...04.00783

EDIT:
Whoops, I see what you mean!!! I thought you'd hit the lower link that describes what arxiv is.

May 05, 2016
Looks like this should have been the link: http://arxiv.org/...7831.pdf
They missed the "1" at the end.

May 05, 2016
Looks like this should have been the link: http://arxiv.org/...7831.pdf
They missed the "1" at the end.
Forwarded your message per the contact feature (site problems)
hopefully they'll correct it - i found it just as i saw your post, so thanks for the correction
(interesting that cd missed that one - LMFAO)

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.

aspects of plasma
@cd
please note that every single author mentioned in the study are learned experienced and trained in plasma and high energy physics - and all have authored in High Energy Astrophysical Phenomena (astro-ph.HE)

by definition this means they're all educated in plasma physics, as demonstrated by education curriculum required for astrophysics research

therefore your argument is simply regurgitation of a known false claim (means: you're lying again)
until you can provide current reputable evidence, this means you're promoting pseudoscience and a religion, not science

May 05, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.


Perhaps you could link to the EU modelling for x-ray pulsars, to show us how they weren't surprised. Or have they never done any, and just want to snipe at the fringes, as usual, despite never having contributed jack s**t to the field of astrophysics?

This article isn't about the EU though is it. It's about astrophysicists ignorance of plasma physics which is on full display with their accretion columns, magnetic mounds, and heterogeneous crowdworkers....

May 05, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.


Perhaps you could link to the EU modelling for x-ray pulsars, to show us how they weren't surprised. Or have they never done any, and just want to snipe at the fringes, as usual, despite never having contributed jack s**t to the field of astrophysics?

This article isn't about the EU though is it. It's about astrophysicists ignorance of plasma physics which is on full display with their accretion columns, magnetic mounds, and heterogeneous crowdworkers....
- CD
Also please note that although Cap'n Rumpy sings the praises of every single author mentioned in the study as being experienced and trained in plasma & high energy physics, Rumpy herself never exhibits the same knowledge, experience and training, which begs the question of what does Rumpy actually REALLY KNOW about the authors' training & experiences, and the science itself. Or does Rumpy only knows jack s**t too?

May 06, 2016
@o_pervert and all your other socks
which begs the question of what does ... actually REALLY KNOW about the authors' training & experiences
you do know that you can just click the author names in arXiv and get a list of their peer reviewed publications or linked arXiv publications, right?

and that you can view their affiliations, jobs, titles, etc too?

or that you can put their names into google scholar (or even just Google) and actually learn not only what they've published or co-authored, but also where they work, what they're working on, etc

.....

but don't let those facts or the basic use of a search engine interfere with your trolling or stupidity...
you never have before

May 06, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.


Perhaps you could link to the EU modelling for x-ray pulsars, to show us how they weren't surprised. Or have they never done any, and just want to snipe at the fringes, as usual, despite never having contributed jack s**t to the field of astrophysics?

This article isn't about the EU though is it. It's about astrophysicists ignorance of plasma physics which is on full display with their accretion columns, magnetic mounds, and heterogeneous crowdworkers....


So, like I said, point us to the plasma physicists that we should be following. The ones who would not have been surprised by such results. With links, please. Published within the last 10 years. Don't go digging up people who have been dead for 20 years and never published on such matters.

May 06, 2016
CD
Also please note that although Cap'n Rumpy sings the praises

Cap'n Stoopid sings the praises of ignorance and ultimate stupidity. Whether it be his idolization of "Pith ball" Timmy Thompson or his irrelevant links he claims to be "proof" that astrophysicists understand real experimentally based plasma physics. Quite frankly I've had Cap'n Stoopid on ignore for over a year and my PhysOrg experience has been much improved. It's easy, just click "Ignore user" and his repetitive incoherent ramblings get muted. Try it sometime.

May 06, 2016

So, like I said, point us to the plasma physicists that we should be following.

Quite likely they'd be the ones whom understand that electrochemical processes occur in plasmas, unlike yourself. They'd understand that ion sputtering is just ion sputtering and not some special "ion sputtering that only occurs on comets" such as you claim. They'd understand the implications of laboratory plasma experiments and how they are relevant to observation. They would not be so eloquent in double speak as you are, such as you acknowledging electrical effects like electric fields, currents, and sputtering and then claim no electric "woo" is occurring. They would understand that all particle and energy exchange that occurs in plasmas is considered electric discharge without exception. Basically they'd be the opposite of you in just about every way.

May 06, 2016
his irrelevant links he claims to be "proof" that astrophysicists understand real experimentally based plasma physics...They'd understand the implications of laboratory plasma experiments and how they are relevant to observation
@cd
and it will take only one link to prove you are not only wrong, but blatantly ignoring information because it proves you to be intentionally stupid as well:
http://www.pppl.gov/about

still don't think scientists learn plasma physics?
this link proves you wrong (yet again):
http://ocw.mit.ed...ophysics

why only one school listed?
because it represents the required curriculum for astrophysics, which include plasma physics

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.

repeating the same tired lie when it's proven false?
this is called religious fanaticism
or
intentional stupidity

take your pic

point being: you've no evidence to offer from the eu
only false claims

epic fail

May 08, 2016
Surprise, surprise, surprise. More "unexpected" aspects of plasma processes.

No surprise that cantdrive still can't drive... ;)

May 08, 2016
The whole comment thread is composed of nutjob "electric universe" posts and responses thereto with no discussion of, wait for it, the actual article.

C'mon, humor me, just one post on the actual physics of neutron stars, please.

And hey PhysOrg, get your act together and edit the article to have the link go to the correct arXiv article, please.

May 08, 2016
The whole comment thread is composed of nutjob "electric universe" posts and responses thereto with no discussion of, wait for it, the actual article.

And who brought up the EU? The one who gets emotional and her panties in a wedgie, jonesdumb.


C'mon, humor me, just one post on the actual physics of neutron stars, please.

Not possible! Physics deals with the science of real stuff, just as you cannot describe unicorns via science, you cannot describe fanciful mathematical entities with physics.

May 09, 2016
And who brought up the EU?
@cd
you did, in your first post where you attempt to denigrate science with your confusion and a poor attempt to prove your second post "It's about astrophysicists ignorance of plasma physics"... all of which is debunked by simply reading the author affiliations as well as education

.

.

continuing to repeat a blatantly false lie that has been repeatedly debunked over the years doesn't demonstrate anything like "the science of real stuff" either...

it demonstrates the cult like mentality of the eu as well, because you can't argue anything substantive, you can only present repeatedly debunked claims

May 10, 2016

cantdrive85 1.4 /5 (11) May 05, 2016
Surprise, surprise, surprise...


that the most mindless comment
On the thread
Is from CD85!

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