Abstract

We measure the alignment of galaxy ellipticities in the local universe over a range of scales using digitized photographic data from the SuperCOSMOS Sky Survey. We find for a magnitude cut of b_J sg^2(theta) > 1 x 10^{-5} for cell side lengths between 15 < theta < 100 arcminutes. Considering the low median redshift of the galaxies in the sample and hence the relatively low effective cross-section for lensing of these galaxies by the large-scale structure of the Universe, we propose that we have detected an intrinsic alignment of galaxy ellipticities. We compare our results to recent analytical and numerical predictions made for the intrinsic galaxy alignment and find good agreement. We discuss the importance of these results for measuring cosmic shear from upcoming shallow surveys (e.g. Sloan Digital Sky Survey) and we outline how these measurements could possibly be used to constrain models of galaxy formation and/or measure the mass distribution in the local universe.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call