Day 1374

Monday.

1802.08263
Measuring the scale-dependence of intrinsic alignments using multiple shear estimates
Leonard, Mandelbaum

Present a new method for measuring the scale-dependence of the IA contamination to the gglensing signal, which takes advantage of multiple shear estimation methods applied to the same source galaxy sample.  By exploiting the resulting correlation of both shape noise and cosmic variance, the method can provide an increase in the S/N of the measured IA signal as compared to methods which rely on the difference of the lensing signal from multiple photometric redshift bins.  For a galaxy-galaxy lensing measurement which uses LSST sources and DESI lenses, the S/N on the IA signal from the method is predicted to improve by a factor of ~2 relative to the method of Blazek+2012, for pairs of shear estimates which yield substantially different measured IA amplitudes and highly correlated shape noise terms.  Show that statistical error necessarily dominates the measurement of IA using this method.  Also consider a physically motivated extension of the Blazek+2012 method which assumes that all nearby galaxy pairs rather than only excess pairs, are subject to IA.  In this case, the S/N of the method of Blazek+2012 is improved.