[Cosmo-media] New Scientist journalist's question(s)

[Boud Roukema]

hi cosmo-media,

A science journalist wants an interview, most probably about
http://arXiv.org/abs/0801.0006, so that s/he can choose one sentence
to publish from a telephone conversation of probably 10-20 minutes or
more....

The journalist refuses to use electronic communication, even jabber!

S/he will probably telephone tomorrow Friday 4 Jan 2008 at 15:00.

S/he also wants our comments on Niarchou & Jaffe (NJ07):

http://arxiv.org/abs/astro-ph/0702436v2
http://space.newscientist.com/article/mg19225811.300-fold-testament-what-shape-is-the-universe.html

My initial thoughts are:

# practical: to get the references to 0702436, download the source
and paste the .bbl file into the .tex file, then latex && latex && dvips

* the NJ07 method is less physically direct than ours, since it
focuses on spherical harmonics on the 2-sphere rather working directly
in comoving 3-space;

* NJ07 is a perturbation simulation approach: the limitations
of this approach are described in Section 1.2.1 of 
Roukema (2000) MNRAS, 312, 712, arXiv:astro-ph/9910272;

* specifically, they assume that even on the largest scales, the
function P(k) is a power law k^n function and that the phases of the
perturbations are Gaussian distributed, which at the largest scales
in a multiply connected universe is an assumption with neither
observational nor theoretical support - it might be right, it might
be wrong;

* the closest papers to their method are probably Caillerie et
al. 2007 arXiv:0705.0217 which works directly with the eigenmodes of
the PDS, up to k = 230, where k = l \frac{R_C}{c/H_0}, and and Aurich
2005b arXiv:astro-ph/0412569; NJ07 use up to "beta" = 41 which seems
to more or less correspond to k, i.e. they have 5 times less
resolution than Caillerie et al.;  Caillerie et al's conclusion
is that the PDS fits WMAP better than the infinite flat model; 
Aurich et al. say that it's not yet possible to make "firm" 
conclusions.

* apart from the normalisation of their probabilities, their Fig. 5
looks like it agrees with Aurich et al. and Caillerie et al for
Omega_{tot} \sim 1.015-1.018


However, the journalist probably wants "sound bites" for the 
"human interest factor" rather than "just science". My suggestions
for sound bites if it's about NJ07:

* "NJ07 have done some interesting work, but their method requires
making some assumptions about theoretical models which have no
physical motivation to be correct on the largest scales of a PDS
universe. We avoid making this type of assumption and use the
observations directly."

* "The apparent space associated with the PDS is the three-dimensional
space called the hypersphere or 3-sphere.  So we work in the
hypersphere, embedded in Euclidean 4-space, which makes it relatively
easy to work with. NJ07 work primarily on the 2-sphere instead of on
the 3-sphere. This could cause some problems."

* "We agree with their final phrase 'the issue of the topology of the
Universe is far from settled'."


As for sound bites about our own work.... i don't have any good ideas
so far.

pozdr
boud