What Lies Beneath: Using p(z) to Reduce Systematic Photometric Redshift
  Errors
  We use simulations to demonstrate that photometric redshift "errors" can be
greatly reduced by using the photometric redshift probability distribution p(z)
rather than a one-point estimate such as the most likely redshift. In principle
this involves tracking a large array of numbers rather than a single number for
each galaxy. We introduce a very simple estimator that requires tracking only a
single number for each galaxy, while retaining the systematic-error-reducing
properties of using the full p(z) and requiring only very minor modifications
to existing photometric redshift codes. We find that using this redshift
estimator (or using the full p(z)) can substantially reduce systematics in dark
energy parameter estimation from weak lensing, at no cost to the survey.
