[time-nuts] Pulsar Source?

Magnus Danielson magnus at rubidium.dyndns.org
Thu Mar 29 22:17:33 UTC 2012


On 03/29/2012 01:50 AM, Jim Palfreyman wrote:
> Folks, I'm currently writing my thesis on pulsars, but I need to spend time
> on it rather than here. :-) But since a lot of this discussion is right at
> the front of my brain, here's a summary.
>
> Some pulsars "glitch" or speed up. The Vela pulsar (PSR J0835-4510) does
> this (this is the pulsar I've been studying) and yes these type of pulsars
> are bad clocks. A jump of its pulse rate of the order of 10^-6 s/s randomly
> every few years is not good. It does nearly settle back to its original
> rate after a few months.
>
> The nature of these glitches (in Vela at least) is not well understood, but
> three theories have been put forward:
>
>     - An orbiting planet - but this has been discarded due to their
>     irregularity.
>     - Star quakes caused by a separation of the crust on the surface of the
>     neutron star from its super-fluid interior. (Not very popular any more)
>     - The effects of tiny micro vortices in the internal super-fluid. (If
>     you can understand this paper - good luck to you!)
>
> Now faster pulsars, in particular millisecond pulsars (~700 Hz from memory
> is the fastest) are quite good clocks and they do rival atomic clocks. The
> hunt is on to find as many of these as they can, well spread across the
> sky, so they can look at the effects of gravitational waves on the beams of
> these super accurate clocks. This is one proposed method to detect
> gravitational waves.
>
> The main problem I see from the original suggestion is that most pulsars
> are quite faint and you need a very decent telescope to see individual
> pulses. Vela is very bright, and the 26m telescope I used can only just see
> the average pulse. I'm studying bright pulses and we can see those easily.
>
> So to dedicate a massive radio telescope (or two) pointing at a millisecond
> pulsar just so we can re-transmit it, is probably not sensible. However,
> studies of these remarkable pulsars is ongoing.

Hmm, wouldn't the space-located antenna have a good chance of better S/N 
as the antenna sees cold space and could be kept cold itself?

I was also thinking antenna size would be a limitation. Then I was 
thinking about what WMAP has achieved in measuring the background 
temperature and look back at the very early years of the universe.

Cheers,
Magnus

Cheers,
Magnus



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