Boud Roukema boud w
Czw, 25 Mar 2004, 10:54:39 CET


On Thu, 25 Mar 2004, Andrzej Marecki wrote:

> astro-ph/0403111
> Date (v1): Thu, 4 Mar 2004 03:41:19 GMT   (12kb)
> Date (revised v2): Fri, 12 Mar 2004 04:15:48 GMT   (12kb)
> Date (revised v3): Mon, 22 Mar 2004 02:04:28 GMT   (12kb)
> Date (revised v4): Wed, 24 Mar 2004 04:03:35 GMT   (0kb,I)
> Problems with studying topology of the universe via circles from cosmic
> microwave background data.
> Authors: Evelise Gausmann, Reuven Opher
> Comments: This paper has been withdrawn

Here's their new abstract:

> This paper has been withdrawn by the authors for future revision.

IMHO, the paper (e.g. v3) has a few misunderstandings of what other
people had already done or explained.

- Their first point (Fig. 1) has been briefly discussed in my paper
astro-ph/0007140, Section 2.1, for the COBE resolution.

- E.g. Fig 2 shows two regions e and f which add different signals to
sky regions which should be multiply imaged. But this is what the
authors have already referred to as "these problems can be minimized
.." - integrated SW and foreground contamination, so they thought they
had a new problem, which was different to ISW and foreground problems,
but really they're talking about the same problem.

- They also state (2nd last paragraph) that "Cornish et al. [3] ...
[make the] assumption that the k-mode fluctuations making contact
with the circles are identical." If that were true, of course it would
be a bad assumption by Cornish et al, but i'm sure they did not make
this assumption.

My own argument (e.g. in section 1.2.1 of astro-ph/9910272) regards
the assumptions about the statistics of the perturbations ("k-mode
fluctuations") which may be sufficiently wrong to invalidate a
simulation, but that's unrelated to making the statement that Gausmann
and Opher made. In fact, the problem is that any eigenmode (or
"k-mode") fills the whole 3-manifold, whether these are eigenmodes of
the fundamental domain (which they should be) or of the covering space
(which would be wrong), so it's not really clear what the authors were
thinking when they wrote the sentence...

Anyway, it's good that people are thinking about the geometry.


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