Astronomers provide new estimate for neutrino mass
WiggleZ in the space-time continuum
The WiggleZ sky survey, which last year announced that its map of 240,000 galaxies provided strong evidence for “dark energy”, has now formed the basis for a new estimate of neutrino mass.
Neutrino mass has proved elusive: it’s easier to measure the difference between the masses of different neutrino species than it is to gain a “baseline” absolute neutrino mass.
According to the University of Queensland, whose Dr Signe Riemer-Sørensen is lead author of a study published by the American Physical Society (abstract here ), the huge amount of data provided by the WiggleZ survey “used the Universe as a large-scale particle physics experiment”.
The survey data sought to use astronomers’ understanding of galaxy formation to help constrain the mass range of the neutrino. In particular, the scientists focused on high-redshift, star-forming, and blue galaxies in the WiggleZ sample.
A mixture of analytical modeling and simulation provides them with a “95% confidence” estimate of neutrino mass: ∑mν<0.60 eV, with the other end of the scale at ∑mν<0.29 eV, “the strongest neutrino mass constraint derived from spectroscopic galaxy redshift surveys”.
The upper limit is considerably greater than previous estimates gleaned from galactic surveys.
To put that in perspective: the rest mas of the electron is around 0.511 MeV – roughly one to two million times the neutrino mass estimated by Riemer-Sørensen’s group (which also included scientists from the USA, South Africa and Canada).
The WiggleZ survey was conducted between August 2006 and January 2011, and its data is online here . ®