KiDS-450: Testing extensions to the standard cosmological model [CEA]
Since I’ve just attended a seminar in Cardiff by Catherine Heymans on exactly this work, I couldn’t resist reblogging the arXiver entry for this paper which appeared on arXiv a couple of days ago.
The key finding is that the weak lensing analysis of KIDS data (which is mainly to the distribution of matter at low redshift) does seem to be discrepant with the predictions of the standard cosmological model established by Planck (which is sensitive mainly to high-redshift fluctuations).
Could this discrepancy be interpreted as evidence of something going on beyond the standard cosmology? Read the paper to explore some possibilities!
http://arxiv.org/abs/1610.04606
We test extensions to the standard cosmological model with weak gravitational lensing tomography using 450 deg$^2$ of imaging data from the Kilo Degree Survey (KiDS). In these extended cosmologies, which include massive neutrinos, nonzero curvature, evolving dark energy, modified gravity, and running of the scalar spectral index, we also examine the discordance between KiDS and cosmic microwave background measurements from Planck. The discordance between the two datasets is largely unaffected by a more conservative treatment of the lensing systematics and the removal of angular scales most sensitive to nonlinear physics. The only extended cosmology that simultaneously alleviates the discordance with Planck and is at least moderately favored by the data includes evolving dark energy with a time-dependent equation of state (in the form of the $w_0-w_a$ parameterization). In this model, the respective $S_8 = sigma_8 sqrt{Omega_{rm m}/0.3}$ constraints agree at the $1sigma$ level, and there is `substantial concordance’ between…
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In the Dark 
October 25, 2016 at 3:38 pm
Peter what is your take on Oxford’s group latest analysis of the SN data?
October 26, 2016 at 10:53 am
http://www.nature.com/articles/srep35596
October 26, 2016 at 1:04 pm
Please see my latest post: https://telescoper.wordpress.com/2016/10/26/a-non-accelerating-universe/
October 26, 2016 at 5:24 pm
Thanks, Peter. I am also curious to hear your take on Stacy’s paper on radial acceleration relation in rotationally supported galaxy and related responses and counter-responses to that paper.
October 26, 2016 at 5:28 pm
I haven’t seen that one.
October 26, 2016 at 7:39 pm
https://arxiv.org/abs/1609.05917, in particular Fig 3 and equation 4. Do you have a trivial explanation of why the total acceleration is a simple parametric equation of only the baryonic acceleration, especially if most spiral galaxies are dark matter dominated? (arxiv trackback links to some press releases about this paper)
This paper already has 2 citations claiming that it can be explained using feedback processes, including 1 rebuttal. I would be very curious on your take on this.
August 4, 2017 at 10:54 am
[…] The central values of DES and Planck values are different, but the discrepancy is only marginal. Compare this with a an equivalent diagram from a paper I discussed last year. […]