From: apj@astro.berkeley.edu
To: sergeib@lanl.gov
Subject: Your ApJ Submission MS# 72617
Date: Mon, 26 Nov 2007
Dr. Sergei Bashinsky
Theoretical Division
P.O. Box 1663, Mail Stop B285
Los Alamos, NM 87545 USA
Dear Sergei:
Enclosed please find the referee's report on your submission to the ApJ entitled
"Mapping Cosmological Observables to the Dark Kinetics" by Sergei Bashinsky ( MS# 72617).
When you resubmit the manuscript, please include a detailed cover letter containing the (mandatory)
listing of the changes you've made to the text and your responses to the report.
Processing of your revised manuscript will be expedited if you make your revisions
to the manuscript latex file available for downloading from the ApJ Web Peer Review System
(http://mss.uchicago.edu/ApJ/). This version includes your previous submission plus any modifications
to latex commands necessary for smooth processing by the ApJ electronic system.
The associated PDF file is the version seen by the referee.
If you have any questions, feel free to contact me.
Best regards,
Chung-Pei Ma, Scientific Editor
The Astrophysical Journal
[contacts]
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In this paper the author addresses the question of how much we can learn about the 'dark sector'
of the universe from CMB anisotropies & polarization and from large scale structure,
in short from observations of clustering in the universe.
I think this is a timely interesting problem and the present paper contains sufficient results
on the subject to warrant publication.
I would like the author to consider the following suggestions:
1) The paper is a bit long for its content, so in certain places where it is mainly reviewing
results from the literature in can be shortened.
2) c_a^2(z,k) defined in Eq. 15 diverges if \delta\rho_a^c
vanishes. Furthermore, it is a ratio of two small first order quantities,
so it can be large. Furthermore, since according to (15) c_s^2 can depend on k terms
like c_s^2\nabla^2\de\rho become convolutions in k-space. (f(x)g(x) -> (f*g)(k) = \int d^3q f(k-q)g(q) ).
I would like the author to comment on this.
I actually think that (15) only makes sense if c_a^2 is independent of k and can be defined
with the background quantities alone.
3) On page 19 in the par. of \sigma_\nu, I think the paper by Trotta & Melchiorri (Phys.Rev.Lett. 95 (2005) 011305)
should be commented on.
4) The author should also comment on the 'dark degeneracy' discussed by Kunz (arXiv:astro-ph/0702615).
After consideration of these comments I feel that this paper can be published in ApJ.