Figure 1: Redshift range over which upcoming observations may probe the cosmic density. Error bars are a forecast for the SNAP satellite.

Please click here to get a postscript file with the paper.
Click here if you are interested in other research of mine. 

Measuring the metric:
a parametrized post-Friedmanian approach to the cosmic dark energy problem


Max Tegmark


We argue for a ``parametrized post-Friedmanian'' approach to linear cosmology, where the history of expansion and perturbation growth is measured without assuming that the Einstein Field Equations hold. As an illustration, a model-independent analysis of 92 type Ia supernovae demonstrates that the curve giving the expansion history has the wrong shape to be explained without some form of dark energy or modified gravity. We discuss how upcoming lensing, galaxy clustering, cosmic microwave background and Lyman alpha forest observations can be combined to pursue this program, which generalizes the quest for a dark energy equation of state, and forecast the accuracy that the proposed SNAP satellite can attain.

Reference info:

astro-ph/0101354, Phys. Rev. D, in press


My most recent estimates of cosmological parameters within the more conventional context are here. You'll find some earlier work of mine on combining different types of complementary data here.

Figure 7: Shaded regions show ranges of scale and redshift over which various observations are likely to probe the linear growth factor over the next few years. The lower left region, delimited by the dashed line, is the non-linear regime.

Return to my home page
This page was last modified September 17, 2002.