MIT Technology Review: Einstein@Home Project Discovers 24 New Pulsars in Old Data

Bernd Machenschalk
Bernd Machenschalk
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Topic 196802

MTR article.



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MIT Technology Review: Einstein@Home Project Discovers 24 New Pu

"cannot detect pulsars with frequencies higher than 160Hz"
Two solar masses circling each other more than 150 times a second? The universe is a wonderful (and a little scary) place to live in.

Or is it "just" the pulsar themselves spinning at 160Hz?

Neil Newell
Neil Newell
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Higher up in the article it

Higher up in the article it mentions "no previous approach has been able to identify binary pulsars with an orbital period of less than 3 hours" until E@H came along. A pulsar with an orbitable period of 1/160s would (at a laymans guess) emit enough gravitional radiation to be easily detectable.

Fastest pulsar known is 716Hz, and it's thought they'd break part around 1500Hz. According to this wikipedia article above 1000Hz they lose energy by gravitational radiation faster than they can spin up.

How fast can pulsars orbit, when they're about to coalesce? Fig. 3 in this paper I just found seems to imply it can be hundreds of Hz - or am I reading it wrong?

Mike Hewson
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Yeah, the numbers spook a bit

Yeah, the numbers spook a bit when you think in everyday terms! These stars are each somewhere between one to two Sun's mass, each compressed into the size of a city's centre and are whizzing around each other before they collide and merge. I think of neutron stars as 'nearly black holes' and their kinetic energy, their magnetic fields, their radiation, the distortion of space and time around them is awesome. Imagine the tides they kick up! A good thing for us they are not nearby! :-)

As the article mentions, prior search techniques fade in effectiveness when the system changes alot over the time of observation, so the newer 'de-Dopplering' approach winkles out the faster changing systems. Rarer birds, at least compared with the known set.

Cheers, Mike.

( edit ) And of course it is way cool that E@H - that's all of us - have contributed to this new knowledge. Even if you personally don't find a pulsar, you still contribute to testing and characterising these new search methods.

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

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