QUASARPOL: A catalog of quasar linear polarisation data

Quasar polarisation measurements are of great importance for understanding the geometry of the inner regions surrounding supermassive black holes. Unfortunately, measurements are generally heterogeneous, and spread over hundreds of papers published in the literature. At the exception of some recent catalogs available on VIZIER or via the Virtual Observatory, there is no dedicated facility to explore those data. This matter of fact, strongly limits the exploitation of polarisation data. For the early papers, that have pioneered the field of quasar polarimetry and gathered numerous polarisation measurements, tables are not available in electronic format, further complicating the use of those invaluable data. We will present QUASARPOL, an effort for constructing a first unified catalog of several thousands of optical linear polarisation measurements of quasars and blazars. An overview of the actual catalog structure, technical difficulties, and of the status of the collected data will be presented. This catalog aims at providing an easy access to polarisation data for the community (familiar or not with polarisation measurements). The current catalog will not be exhaustive. We rather encourage its completion in a collaborative manner, with spontaneous contribution from the community in a simple tabular format.