End user use cases: * Discover steps of production (backward search) which processing steps have been done already? * Find all descendants of a dataset that are accessible through the VO e.g. higher level products derived from a dataset * Find help contact Who can I ask about these data? * Find who generated the data who are the creator, provider, publisher, curator... provider = CTA, HST, scientist publisher = data center, web service, * Give attribution Who was involved in the project? * Open provenance information in a standard tool to view and explore it * Combine provenance information from different observatories/projects Ex: add X-ray and radio contours on top of a gamma-ray image with links to their provenance Producer use cases: * Aid in debugging Find possible error sources, e.g. check version of processing software, ambient conditions, telescope configuration, parameter settings, ... * Allow to assess the quality of the data Both: * Aid in reprocessing * Reproduce a result or intermediate data Requires more details * Search in structured provenance metadata * Locate the progenitor(s) of an entity * Locate output files affected by a bug in an input file or activity (forward search) Minimum Requirements: * Provenance information must be stored in a standard model, with standard serialization formats * Provenance data model classes and attributes should be linked to other IVOA concepts when relevant (ObsCoreDM, SimDM, VOTable, UCDs...) * Provenance information must be machine readable * Provenance information should be serializable into the W3C PROV standard formats with minimum information loss * All produced entities must contain information to find its immediate progenitor(s) * All produced entities must contain information to find the activity that generated it * Activities must have links to input and output entities * Provenance information should contain the list of activities and progenitor entities * Released entities must have a unique, persistent identifier (DOI, obs_publisher_did, ...) * Released entities must have a main contact * It is recommended that all activities and entities have contact information and link to a description * The order of the activities should be kept * Activities should be defined by... (see working draft and data model) * Entities should be defined by... (see working draft and data model)