Search for Small Scale Dark Matter Structure in HDF with New Lensing Method.
Marina Shmakova
Stanford Linear Accelerator Center
shmakova@slac.stanford.edu
Additional authors: John Irwin, Marina Shmakova
On the premise that small-impact-parameter scattering from dark matter would produce a correlation in the orientation of sextuple and quadruple moments in background galaxy images, we identified these "slightly curved" galaxies in the Hubble deep field and found them to be strongly clustered. We have modeled each galaxy with an adjustable radial shape followed by a map containing quadruple, sextuple and other high-order terms, convolved this form with the appropriate sub-sampled Tiny Tim PSF, dithered, diffused and then dropped images onto the HSF pixel-sized grid. Signal-to-noise ratios were determined based on photon counts and radial galaxy moments, and cuts were performed to insure map coefficients could be determined with the accuracy required to distinguish curved galaxies. Studies of same-z background galaxies indicate that the observed clumping is unlikely to arise from an intrinsic correlated curvature.
