Precision Weak Gravitational Lensing Using Velocity Fields: Fisher Matrix Analysis

Abstract Weak gravitational lensing measurements based on photometry are limited by shape noise: the variance in unknown unlensed orientations of source galaxies. If is a disk galaxy with well-ordered velocity field, however, field data can support simultaneous inference shear, inclination, and position angle, virtually eliminating noise. We use Fisher information matrix formalism to forecast precision this method idealized case perfectly ordered defined an infinitesimally thin disk. For nearly face-on targets, one shear component, γ × , be constrained where I 0 signal-to-noise ratio central intensity pixel n pix number pixels across diameter enclosing 80% light. This degrades inclination angle factor 3 i = 50°. The uncertainty other + about 1.5 (7) times larger than for targets at 10° (50°). arbitrary sky, these forecasts apply not as sky but two eigenvectors ( μ ) space, magnification. also potential less expensive partial observations such slit spectroscopy. conclude outlining some ways which real galaxies depart from our model thus create random or systematic uncertainties captured here. In particular, currently only quality rather scatter properties because relevant type has yet measured.