DMTN-049 DRAFT

# LSST DRP (Level 2) \\ Catalog Photometric Redshifts

• M. L. Graham

## Abstract

The purpose of this document is to begin to assemble the diversity of motivations driving the inclusion of photometric redshifts in the LSST Level 2 Object Catalog, and prepare to make a decision on what kind of photo-$z$ products will be used. The roadmap for this process is described in Section \ref{sec:intro}. We consider the photo-$z$ use-cases in order to validate that the type of photo-$z$ incorporated into the Level 2 DRP catalog, and the format in which it is stored, meets the needs of both DM and the community. We also compile potential evaluation methods for photo-$z$ algorithms, and demonstrate these options by applying them to the photo-$z$ results of two off-the-shelf photo-$z$ estimators. The long-term plan is for this document to develop over time and eventually describe the decision-making process and the details of the selected algorithm(s) and products. \textbf{Preliminary recommendations can be found in Section \ref{sec:intro}.}