Self calibration of gravitational shear-galaxy intrinsic ellipticity
  correlation in weak lensing surveys
  The galaxy intrinsic alignment is a severe challenge to precision cosmic
shear measurement. We propose to self-calibrate the induced gravitational
shear-galaxy intrinsic ellipticity correlation (the GI correlation,
\citealt{Hirata04b}) in weak lensing surveys with photometric redshift
measurement. (1) We propose a method to extract the intrinsic
ellipticity-galaxy density cross correlation (I-g) from the galaxy
ellipticity-density measurement in the same redshift bin. (2) We also find a
generic scaling relation to convert the extracted I-g correlation to the
demanded GI correlation. We perform concept study under simplified conditions
and demonstrate its capability to significantly reduce the GI contamination. We
discuss the impact of various complexities on the two key ingredients of the
self-calibration technique, namely the method to extract the I-g correlation
and the scaling relation between the I-g and the GI correlation. We expect none
of them is likely able to completely invalidate the proposed self-calibration
technique.
