First Evidence of Intrinsic Alignments of Red Galaxies at z > 1: Cross Correlation between CFHTLenS and FastSound Samples

We report the first evidence for intrinsic alignment (IA) of red galaxies at z > 1. We measure the gravitational shear-intrinsic ellipticity cross correlation function at z similar to 1.3 using galaxy positions from the FastSound spectroscopic survey and galaxy shapes from the Canada France Hawaii telescope lensing survey data. Adopting the nonlinear alignment model, we obtain a 2.4 sigma level detection of the IA amplitude A(LA) = 27.48(-11.54)(+11.53)(and 2.6 sigma with A(LA) = 29.43(-11.49)(+11.48) when weak lensing contaminations are taken into account), which is larger than the value extrapolated from the constraints obtained at lower redshifts. Our measured IA is translated into a similar to 20% contamination of the weak-lensing power spectrum for the red galaxies. This marginal detection of IA for red galaxies at z > 1 motivates the continuing investigation of the nature of IA for weak lensing studies. Furthermore, our result provides the first step to utilize IA measurements in future high-z surveys as a cosmological probe, complementary to galaxy clustering and lensing.