Detection of a dipole in the handedness of spiral galaxies with redshifts z∼0.04

A preference for spiral galaxies in one sector of the sky to be left-handed or right-handed spirals would indicate a parity violating asymmetry in the overall universe and a preferred axis. This study uses 15,158 spiral galaxies with redshifts <0.085 from the Sloan Digital Sky Survey. An unbinned analysis for a dipole component that made no prior assumptions for the dipole axis gives a dipole asymmetry of −0.0408±0.011 with a probability of occurring by chance of 7.9×10−4. A similar asymmetry is seen in the southern Galaxy spin catalog of Iye and Sugai. The axis of the dipole asymmetry lies at approx. (l,b)=(52°,68.5°), roughly along that of our Galaxy and close to alignments observed in the WMAP cosmic microwave background distributions. The observed spin correlation extends out to separations ∼210 Mpc/h, while spirals with separations <20 Mpc/h have smaller spin correlations.