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Comment pulsars are nature's flywheels (Score 1) 325

All of the energy that we see (as well as the energy we don't see, which is the vast majority of it and which comes out in a relativistic particle wind) comes from the rotation of the neutron star. That means that pulsars are flywheels. And amazingly (even to me, and I study them daily), the most energetic pulsars give off tens of thousands of times more power than the total power output of the Sun. And all from rotation. That's crazy.

Damn the Universe is cool.

Comment Re:Telescope in West Virginia (Score 4, Informative) 248

Actually, they aren't using the GBT's spectrometer. They are using an instrument that I helped to develop for pulsar research called GUPPI, which uses FPGAs and GPUs to real-time process 800MHz of radio bandwidth.

However, in this case they are using GUPPI's GPU nodes to record 800MHz of Nyquist-sampled band centered at 1.5GHz. Each sample is 2-bits, and with 2 polarizations, that is how they get 800MB/s (or almost a GB/s as it says in the article).

If you want some basic info about GUPPI, you can find it here:

https://safe.nrao.edu/wiki/bin/view/CICADA/NGNPP

Comment Re:A complementary approach (Score 5, Informative) 190

The good thing is that the pulsars which glitch are the young ones (hundreds to millions of years old). The pulsars that we are using for NANOGrav are millisecond pulsars which are hundreds of millions or billions of years old, have much smaller magnetic fields than young pulsars, and basically never glitch. They are extremely stable rotators -- much better than normal pulsars.

Comment Re:Or better yet, don't write Congress (Score 2, Interesting) 171

There is no compelling science case for Arecibo that can't be pursued with other telescopes, especially since the frontier of radio astronomy has mostly moved from sensitivity (requiring big apertures) to resolution (requiring long-baseline arrays), or to shorter mm/submm wavelengths that Arecibo can't handle.

Sorry, but that is not true. Radio astronomy needs improvement in a wide variety of areas in order to tackle the tremendously wide variety of science that is done at radio bands. Examples include sensitivity, field-of-view, dynamic range, image fidelity, resolution, and wavelength coverage. But sensitivity is one of the most important. That is why the SKA is on the table to be the world's next generation decameter/centimeter wave radio telescope. The most important thing it provides is sensitivity (i.e. SK = square km = sensitivity). And Arecibo is already a 5-10% SKA.

For my own research (pulsars), Arecibo's sensitivity is what sets it apart. Although, truthfully, the fact that it can't observe any of the southern sky (where most of the pulsars are) is a definite downside.

Finally, you mention surveys and imply that because Arecibo is doing a larger percent of them now that that means it is washed up. However, that also isn't true. Modern astronomy is driven by large surveys (including several of the instruments that you mention, for example, Sloan, PANSTARRS, LSST) as they dramatically increase our discovery space.

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