Petr
There are thorns that determine the location of the density maximum and/or the centre of mass for neutron stars, and those thorns can feed into Carpet's regridding method to have it track neutron stars. I have not evolved moving neutron stars myself, so I can't tell you any more details, but I hope others on this list will speak up.
Another method (that is probably not implemented yet) would be to track the centre of the neutron stars in the same manner as the puncture tracker, i.e. to derive an ODE that drives a pseudo-particle along the density gradient. (In the puncture tracker, this pseudo-particle moves along the shift vector instead.)
-erik
On Mon, Jan 16, 2012 at 6:03 PM, Petr Tsatsin ptsatsin@fau.edu wrote:
Hello , I'm trying to test a new version of my thorn which sets up initial data for moving neutron star. And I have couple questions about the Carpet moving grids. I was wondering if you could help answer it or suggest some recent documentation for Carpet which I can refer to? The question is simple: How to move grids in case of the moving neutron star? By looking at bbh parameter file I understood that Carpet gets information about position of the puncture from puncture tracker. Is there any trons which is providing this information in case of a neutron star or I have to write some thorn which is actually will track a center of the neutron star or its surface? Thank you!
-- Petr Tsatsin Graduate Student - Department of Physics Charles E. Schmidt College of Science Florida Atlantic University (561)-297-3386 cell: 561-692-2040 ptsatin@fau.edu, ptsatsin@gmail.com
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