Confirmation of general relativity on large scales from weak lensing
and galaxy velocities
Nature, 7286 (464):
256--258 (марта 2010)DOI: 10.1038/nature08857
Аннотация
Although general relativity underlies modern cosmology, its applicability
on cosmological length scales has yet to be stringently tested. Such
a test has recently been proposed1, using a quantity, EG, that combines
measures of large-scale gravitational lensing, galaxy clustering
and structure growth rate. The combination is insensitive to ‘galaxy
bias' (the difference between the clustering of visible galaxies
and invisible dark matter) and is thus robust to the uncertainty
in this parameter. Modified theories of gravity generally predict
values of EG different from the general relativistic prediction because,
in these theories, the ‘gravitational slip' (the difference between
the two potentials that describe perturbations in the gravitational
metric) is non-zero, which leads to changes in the growth of structure2
and the strength of the gravitational lensing effect3. Here we report
that EG = 0.39 ± 0.06 on length scales of tens of megaparsecs, in
agreement with the general relativistic prediction of EG almost
equal to 0.4. The measured value excludes a model1 within the tensor-vector-scalar
gravity theory4,5, which modifies both Newtonian and Einstein gravity.
However, the relatively large uncertainty still permits models within
f(R) theory6, which is an extension of general relativity. A fivefold
decrease in uncertainty is needed to rule out these models.