NICE work !

Mike Hewson
Mike Hewson
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Topic 220209

I just discovered this NASA initiative that I never knew existed : mapping of a neutron star's surface using high resolution X-ray data. What is especially neat is that the modelling takes particular account of the bending of light in the gravity well surrounding this dense object. That way some regions momentarily on the far side of the star remain visible ! The hot spots are at millions of degrees. Plus more kudos for getting nearly identical results via different analysis teams. This is a groundbreaking discovery. Possible worth a prize, eh ...... ?

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

cecht
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Way cool! Thanks for the

Way cool! Thanks for the link!

 

Ideas are not fixed, nor should they be; we live in model-dependent reality.

Mike Hewson
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Back Of The Envelope : Try

Back Of The Envelope : Try this. A pulsar frequency of 205 Hz gives the pulsar's rotational period at about 5 x 10-3 seconds, whereas the time resolution of the gadget is 100 nanoseconds or 10-7 seconds which is thus 1/50000th of a revolution. Hence the Xray receiver can distinguish the phase of the pulsar's rotation to that order.

That's fantastically good. A boggle in fact. Think of the data stream as a sequence of Xray 'images', some 50000 of them per one revolution of the pulsar. And that sequence repeats with each full rotation if the features of the surface stay pretty much constant over the time of the study. Fold the data stream in time much like we do here at E@H ie. as per source frequency. Soooo ....... provided you can model the self lensing aspect of the neutron star ..... yes, that's it, the star distorts it's own image from 'true' ..... then search for the best fit to the data by going through a set of hot spot templates to try.

Hmmmm. E@H does that sort of template matching work also. E@H delivers solutions that can be measured in modern-desktop-computer-years ..... only we are using gravitons*. :-)

Cheers, Mike. 

* .... if they exist that is.

( edit ) I wonder what feature/criteria of the data allows them to denote one pole as 'north' and the other as 'south' ?

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

lazlo
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Quote:...( edit ) I wonder

Quote:
...( edit ) I wonder what feature/criteria of the data allows them to denote one pole as 'north' and the other as 'south' ?

Aren't polarized particles still bipolar charge-wise?  That is to say wouldn't they still flow in a way that effected what we see enough to detect that flow?

 

Just a layman's guess.

Jim1348
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Mike Hewson wrote:That's

Mike Hewson wrote:
That's fantastically good. A boggle in fact. Think of the data stream as a sequence of Xray 'images', some 50000 of them per one revolution of the pulsar.

Does that allow them to discern "bumps", or at least asymmetries?

Do we confirm their work, or are we made redundant?

Mike Hewson
Mike Hewson
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Jim1348 wrote:Mike Hewson

Jim1348 wrote:
Mike Hewson wrote:
That's fantastically good. A boggle in fact. Think of the data stream as a sequence of Xray 'images', some 50000 of them per one revolution of the pulsar.

Does that allow them to discern "bumps", or at least asymmetries?

The hot spots are an asymmetry, but not in the same sense that we are looking for at E@H. At least I don't think they're expecting a mass feature to be associated with hot spots. Much like the Earth one can have a magnetic pole not coinciding with a rotational pole nor a local mass concentration. Interior structure vs. exterior features I guess.

Quote:
Do we confirm their work, or are we made redundant?

Our work is independent. We seek the type of mass asymmetries that generate gravitational waves. 

As for designating North and South poles : after some thought I think the X-ray data can clearly define a rotational axis. That axis can be expressed with respect to the orientation of the Earth's axis. So one could use our North/South poles to designate with respect to. I mean they won't be identical/parallel directions .... but take the dot product etc. 

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

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