Max Tegmark's library: 9par

Figure 3: When including reionization and gravity waves, the yellow constraints go away, allowing a closed Universe. However, Lambda=0 is still ruled out if you take the supernova 1a constraints seriously.

Please click here to get the postscript file with the paper. Here's color viewgraphs with fig 1, fig 2 and fig 3 - you can also click on the images.
Click here if you are interested in other research of mine. 

Cosmological constraints from current CMB and SN 1a data: 
a brute force 8 parameter analysis


Max Tegmark


We describe constraints on a ``standard'' 8 parameter open cold dark matter (CDM) model from the most recent CMB and SN1a data. Our parameters are the densities of CDM, baryons, vacuum energy and curvature, the reionization optical depth, and the normalization and tilt for both scalar and tensor fluctuations. We find that although the possibility of reionization and gravity waves substantially weakens the constraints on CDM and baryon density, tilt, Hubble constant and curvature, allowing e.g. a closed Universe, open models with vanishing cosmological constant are still strongly disfavored.

Reference info:

astro-ph/9809201, accepted for publication in ApJL
Figure 1: These 3 models are completely different physically, but cant be discriminated by the data.
One has n=1, another n=1.4.

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This page was last modified February 2, 1999.