Wednesday, February 9, 2011

Current Cosmology From Supernova Data.

Ariel Goobar and Bruno Leibundgu have recently submitted an article to Annual Review of Nuclear and Particle Science summing up our current understanding of physics from the current set of supernova data. We have accrued quite a lot of supernova data over the years and so it is interesting to take a look at how much we have learned. I will not report everything but will post a few interesting plots.

Above is the original diagram/scatter plot Hubble used to show the universe is expanding in a way that fits Hubble's law. This is that same diagram today using current supernova data (not a scatter plot any more!): (showing the distance modulous versus redshift.)

As you can see Hubble's law is confirmed by quite a few supernova today. :) Furthermore, the lower plot shows a blue line representing a universe containing cold dark matter and a cosmological constant and a flat dotted line assuming a universe empty of cold dark matter or dark energy/cosmological constant. As can be seen, the supernova data *strongly* favors a universe with dark matter and dark energy/cosmological constant.
The next plot above shows how well we can constrain the percentage of dark matter and dark energy in the universe using supernova, CMB and BAO data. (click on the image to see better.) As you can see the data fits a flat universe with an accelerated expansion very well
The last plot I want to display shows the current constrains we have on the type of beast dark energy is. As a reminder, the prediction we get from dark energy being the cosmological constant is w = -1. As you can see w = -1 still fits the data very well.

Conclusion: It is nice to see as more and more cosmological data pours in the standard flat universe containing dark energy, cold dark matter, accelerated expansion and dark energy best described by a cosmological constant is verified. Cosmology has truly become a precision science.

ResearchBlogging.orgAriel Goobar, & Bruno Leibundgut (2011). Supernova cosmology: legacy and future To Appear In Annual Review of Nuclear and Particle Science arXiv: 1102.1431v1

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