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They show that the mean redshift-magnitude relation from a spectroscopic survey can be used to infer peculiar velocities.

Authors note a new phenomenon: linear portions of quasar lightcurves have gradients that appear vary systematically with quasar redshift (higher z quasars have steeper gradients). Interesting if real: it could sharpen up QSO redshift estimation in cadenced imaging surveys beyond what you can do with the QSO colours.

Recommended by Jo.

Axions are ultra-light particles that arise in string theory, and could make up some part of the dark matter in the universe. If so, what are the prospects for detecting their effects with galaxy surveys/CMB/weak lensing with future experiments? Come and ask the authors.

Pontzen and I were sitting there reckoning axions look a lot like hot dark matter - but I guess there must be some key difference at large angular scales to enable Dodi et al to distinguish between massive neutrinos and axions in a Planck+Euclid combo. Pretty cool :-)

Interesting Nature letter suggested by Pat Roche

Daniel Mortlock talked me through this when I visited ICL recently, its a nice result, especially the deep GP trough. The survey paper (that preceded this one) was interesting too, for its treatment of detection probablity and completeness, worth a look for anyone interesting in finding (and not finding) things.

Discovery of a group of quasars which appear to form a structure over 1 Gpc across. This is much larger than any previously-suggested homogeneity scale in LambdaCDM.

There is a discrepancy between cluster Y_SZ measurements made by Planck and AMI. Yikes!

You can fix the acoustic scale using low-z luminosity distance measurements instead of the high-z CMB measurement. This would be a useful consistency test for LCDM, and can be used to constrain N_eff.

Combining galaxy distribution / clustering measurements with weak lensing shear measurements is a hot topic at the moment and this is the latest attempt to use both to reconstruct the COSMOS density field.

Authors: Lado Samushia,Beth A. Reid,Martin White,Will J. Percival,Antonio J. Cuesta,Lucas Lombriser,Marc Manera,Robert C. Nichol,Donald P. Schneider,Dmitry Bizyaev,Howard Brewington,Elena Malanushenko,Viktor Malanushenko,Daniel Oravetz,Kaike Pan,Audrey Simmons,Alaina Shelden,Stephanie Snedden,Jeremy L. Tinker,Benjamin A. Weaver,Donald G.

A recent-historical analysis of cosmological parameter estimation. "Of the 28 measurements of Omega_Lambda in our sample published since 2003, only 2 are more than 1 sigma from the WMAP results. Wider use of blind analyses in cosmology could help to avoid this."

Their detection of confirmation bias (aka unconscious experimenter bias, or groupthink) may not be so significant: most if not all of those Omega_Lambda measurements will have used WMAP CMB priors. Next step would be to try and correct for that. Their warning for future analyses is spot on though: parameter estimation needs to be done blind.

Boylan-Kolchin et al identify a new problem with CDM at sub-galactic scales: the Aquarius simulated MW galaxy halos have subhalos that are about 5 times more massive than the actual dwarf satellites we see. Are we underestimating the MW satellites' masses somehow? Or is their something wrong with the simulations? Or both? Anyway, as Phil B said: add it to the list of things to investigate about CDM :-)

The observational counterpart? http://arxiv.org/abs/1111.2611

Interesting: Strigari & Wechsler prefer to state the problem as the sims predicting 25-75 times as many subhalos at the Fornax mass scale as are observed in the MW system - and in the paper you posted they look at thousands of MW analogs in the SDSS survey and find that the MW is not atypical. This strengthens MBK's conclusion, that there is a problem with CDM - although note that S&W put the emphasis on galaxy formation not being well understood at this mass scale. They imagine that there really are all those dark Fornaxes out there! Pretty cool - now, if we could just see them somehow...

This set of three papers (the link is to the first one, by Nikhil Padmanabhan) describes a factor of two improvement in the SDSS DR7 BAO distance estimate, just by improving the data analysis. Basically, non-linear gravitational collapse causes the usual BAO feature in the galaxy correlation function to appear smoothed out: it can be partially sharpened back up by using the Zel'dovich approximation to reconstruct the density field given the redshift and position data. The result is an increase in cosmological parameter accuracy roughly equivalent to surveying 3-4 times more sky. Software is vital!

It is interesting to see, in the third paper, how the constraints on H_0 \Omega_m space are robust to different scenarios of curvature and dark energy, and compatible with direct measurements of H_0. But also, as expected, this is effected by what one assumes about the neutrinos.