[Users] [Fwd: Kerr ID]

[Scott Noble]

Hello Erik and Bruno,

   I do not know off-hand a place in the literature where \beta^\phi is 
stated.  \beta^\phi in BL coordinates is rarely expressed since the BL 
metric is usually given in line element form, not in ADM form.

   It should be simple enough to derive it from the other components, 
which (IMHO) are correct.   I could make a maple script that derives it, 
but then you'd have to trust that I wrote up the maple script correctly...

   FYI: I believe

  shift_phi = \beta^\phi    and
  beta_phi = \beta_\phi    .

-- scott n.


On 10/6/10 8:29 PM, Bruno Coutinho Mundim wrote:
> Hi Scott and Erik,
>
> I was also looking into this issue now. The mapping from the PRD 54 1403
> paper to the code documentation seems to go as in:
>
> Paper Documentation
> r r_k
> \bar{r} r
> quasi-isotropic radius \eta ???
>
> Also note that the Sigma definition in the documentation is not the
> usual definition in Boyer-Lindquist coordinates.
>
> I hope there is a reference for the documentation. Otherwise, the
> non-usual notation there prevents us of a simple check.
>
> Thanks,
> Bruno.
>
> Erik Schnetter wrote:
>> Scott
>>
>> Do you have a pointer to literature that contains the correct
>> equation? I'm looking at PRD 54 1403, which is the paper cited in the
>> thorn; is that a good choice? Do you know how the variables in the
>> paper are mapped to the variables in the code? The code documentation
>> (the latex file doc/documentation.tex) seems consistent with the C
>> code, but of course both could be wrong. Or is there an easy way to
>> see why the factor Sigma is missing?
>>
>> I haven't used the Boyer-Lindquist Kerr initial data implemented in
>> this thorn myself; I usually use Kerr-Schild coordinates form thorn
>> Exact.
>>
>> -erik
>>
>> On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble <scn at astro.rit.edu> wrote:
>>> I see that this has not been patched yet. Can someone please confirm the
>>> fix and
>>> patch the repo?
>>>
>>> thanks, scott n.
>>>
>>>
>>> -------- Original Message --------
>>> Subject: Kerr ID
>>> Date: Mon, 07 Jun 2010 16:54:20 -0400
>>> From: Scott Noble <scn at astro.rit.edu>
>>> To: users at einsteintoolkit.org
>>>
>>>
>>> Hello Users,
>>>
>>>
>>> I believe I found a minor typo in
>>>
>>> EinsteinInitialData/IDAnalyticBH/src/Kerr.c
>>>
>>> of the ET. Just a missing term in the denominator of the shift
>>> vector, so
>>> it will not likely affect many users. I have attached a patch.
>>>
>>> cheers,
>>>
>>> -- scott n.
>>>
>>>
>>>
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>>>
>>
>>
>>
>