Can Gamma Ray Bursts Be Used to Measure Dark Energy?
I have previously mentioned an article on a new measurment of dark energy. It was in the Washington Post so it obviously did not present many details. I finally had some time to dig around a little, and I found that the author, Bradley E. Schaefer, has been studying gamma ray bursts for several years and that he was a member of the Supernova Cosmology Project, which was one of the teams that first discovered dark energy.
I found that one of the best explanations can be found at Cosmic Variance. It even has a comment from Schaefer. This result is based on 52 gamma ray bursts. This actually compares favorably with the original dark energy paper using supernovae that had 42 supernova. Interestingly, Schaefer has found more than one way to measure the luminosity for each gamma ray burst, so that he gets 172 independent measures of the luminosity. In his paper he lists other attempts to do this type of measurement and the other groups have always restricted themselves to one luminosity indicator per gamma ray burst.
My impression that this is an interesting new method, but it probably needs some serious study of the systematic errors, and no one should be drawing conclusions yet about the cosmological constant. Of course all of the articles that I have seen have lead with the conclusions about the cosmological constant, while I find the potential of this method the most interesting. It will clearly have very different systematics than the supernovae, and it can look farther back in the history of the universe.
Technorati Tags: physics