Another episode in the Omega_total story
http://arxiv.org/abs/astro-ph/0608632
Cosmological Constraints from the SDSS Luminous Red Galaxies
M Tegmark, et al... [umpteen authors]
Comments: SDSS data and ppt figures available at this http URL 36 PRD pages, 25 figs
"We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). ...
... Our results provide a striking confirmation of the predicted large-scale LCDM power spectrum. ...
...
... For LCDM, our power spectrum measurement improves the evidence for spatial flatness, sharpening the curvature constraint Omega=1.05+-0.05 from WMAP alone to Omega_tot=1.003+-0.010. All these constraints are essentially independent of scales k>0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive analyses where nonlinear modeling is crucial. (Abridged)"
Tegmark et al put it in this interval: [0.994, 1.013]
See their table 3, on page 14
WITHOUT the Sloan Digital Sky Survey, with WMAP ALONE they put it in the interval [1.008, 1.118]
again see table 3
See figures 16 and 17, around page 20. they graphically show how Tegmark et al NARROW DOWN the allowed Omega by supplementing WMAP data with SDSS and stellar ages.
=======always interesting to see how people talk========
Look around page 21
Although it has been argued that closed inflation models require particularly ugly fine-tuning [131], a number of recent papers have considered
nearly-flat models either to explain the low CMB quadrupole [132], in string theory landscape-inspired short inflation models, or for anthropic reasons [108, 133, 134], so it is clearly interesting and worthwhile to continue sharpening observational tests of the flatness assumption. In the same spirit, measuring the Hubble parameter h independently of theoretical assumptions about curvature and measurements of galaxy distances at low redshift provides a powerful consistency check on our whole framework. Figures 15, 16 and 17 illustrate the well-known CMB degeneracies between the curvature...and dark energy ...,
the Hubble parameter h, and the age of the universe ...; without further information or priors, one cannot simultaneously demonstrate spatial flatness and accurately measure Omega_Lambda, h or t_now, since the CMB accurately constrains only the single combination... Indeed, the WMAP3 degeneracy banana extends towards even larger Omega_total than these figures indicate; the plotted banana has been artificially truncated by a hardwired lower limit on h in the CosmoMC software...[/color]
So the slightly positive curved, spatially closed models are being called NEARLY FLAT. that is the term I need to keep an eye out for.
There is some reason that most researchers have preferred to consider the exactly flat case----the paper suggests some reasons having to do with "ugly fine-tuning the inflation"----and yet some other papers have chosen to consider this case: citations [132, 108, 133, 134]. One of these is a paper [108] which Tegmark wrote himself with Martin Rees.
So I would say, based on a brief inspection, that the paper still favors the flat case but that it has some portions which contemplate the NEARLY FLAT case.
, THEY ARE ALL BASED ON THE SAME FEW DATASETS, like SDSS and WMAP which gradually get improved and people keep re-using.