Associated data: Indexation, discovery, challenges and roles

Astronomers are nowadays required by their funding agencies to make the data obtained through public-financed means (ground and space observatories and labs) available to the public and the community at large. This is a fundamental step in enabling the open science paradigm the astronomical community is striving for. In other words, tabular data (catalogs) arriving to CDS for ingestion into its databases, in particular VizieR, is more and more frequently accompanied by the reduced observed dataset (spectra, images, data cubes, time series). While the benefits of making this associated data available are obvious, the task is very challenging: in this context "big data" takes the meaning of "extremely heterogeneous data", with a diversity of formats and practices among astronomers, even within the FITS standard. Providing librarians with efficient tools to index this data and generate the relevant metadata is therefore paramount