Is there further evidence for spatial variation of fundamental constants?

Indications of spatial variation of the fine-structure constant, $\alpha$, based on study of quasar absorption systems have recently been reported [J. K. Webb, J. A. King, M. T. Murphy, V. V. Flambaum, R. F. Carswell, and M. B. Bainbridge, arXiv:1008.3907.]. The physics that causes this $\alpha$-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis and study existing measurements of deuterium abundance for a signal. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio $\mu$ and $x={\alpha }^2\mu g_p$ for spatial variation.

Figure 1

$1\sigma$ confidence regions for the Keck (green triangles), VLT (blue stripes), and combined (plain red) Australian dipoles of $\alpha$-variation in the Hammer-Aitoff projection, taken from 2. The spotted orange region is the $1\sigma$ confidence interval for a dipole in deuterium abundance, where each point on the contour represents a separate minimization of $m_D$ and $d_D$ for a dipole in that direction. The galactic plane (grey) and CMB dipole direction ($P_{\mathrm{CMB}}$) are also shown.

Figure 2

Deuterium abundance vs $r\cos \psi$ (Gly) where $\psi$ is the angle between the measurement direction and the dipole of Ref. 1. Dashed line: monopole fit; solid line: dipole fit (fixed direction). Fit parameters are given in Table .