Closed JonPaulLundquist closed 7 months ago
This paper https://indico.cern.ch/event/258092/papers/1588499/files/4149-crpropa.pdf seems to imply that the size is 186 - 54 Mpc = 132 Mpc. If that's the case I would recommend the file name be changed as that is highly unintuitive... Using:
size = 132*Mpc
b_factor = 0.001 #10*10**9 * nG
I can find Virgo less than 10 degrees from where it's supposed to be at 20 Mpc (a Mpc or so off from Dolag) with a field of 2.4 microGauss. Good enough. It looks like this:
I can also find Perseus a couple of degrees from where it's supposed to be at 69 Mpc ( about 3 Mpc or so off from Dolag) with a field of 2.7 microGauss. Good enough. Though the field is a bit low. It looks like this:
And Coma cannot be found because we're running out of box volume.
Does this appear to be correct? If so, I again recommend changing that file name and changing (or adding) a reference if it can be done.
Hey John you want discuss this through discord or something? Can I have your email? I think I can get the quimby file which is more accurate to Dolag's paper. We could work on using that instead. Here's my email: msalas02@citymail.cuny.edu
I close the issue. If there are still issues please re-open it.
The Dolag magnetic field (dolag_B_54-186Mpc_440b.raw) provided does not include any instructions on how it should be used. Such as the size and b_factor. Loading the field with:
Assuming supergalactic coordinates I would assume that I would be able to pick out the features shown in Figure 12 of the paper CRPropa references for this field (https://iopscience.iop.org/article/10.1088/1475-7516/2005/01/009/pdf). This is not the case. Nor, assuming galactic or equatorial coordinates. This paper seems to use a different field with a different size and grid size. The CRPropa paper (https://arxiv.org/pdf/1603.07142.pdf) also used a different size and number of cells than are compatible with this file.
This is how I'm finding coordinates:
This should give the magnetic field and positions for the grid points in the file. Please also see this thread https://github.com/CRPropa/CRPropa3/issues/373. If the parameters to use this file are unknown it should probably not be provided with an outdated reference.