The ALMA Science Archive Network

The ALMA Science Archive (ASA) will be built up and maintained in Chile (San Pedro and Santiago) and then mirrored to three main ALMA Regional Centers (ARCs) in the USA (NRAO, Charlottesville, VA), Europe (ESO, Garching, Germany) and Japan (specific location to be determined). The archive implementation thus has to support reliable mirroring and transparent access to all data holdings in this global network of scientific data. This paper describes the concepts of the data distribution and the user access to the ASA and presents an outline of the current status. 1. ALMA Archive Deployment The two core archive nodes for the Atacama Large Millimeter Array (ALMA), in San Pedro de Atacama and Santiago, Chile, will provide the front-end and the main science archive node, respectively. The archive node at the Operations Support Facility (OSF) in San Pedro will be fully dedicated to support ALMA operations and will not be accessible externally. The archive node at the Science Operations Center (SOC) in Santiago will serve as the central access point for proposal submission, it will host the primary copy of the full ALMA data archive, and all data will be pushed from there to the three ALMA Regional Centers (ARCs). The ARCs will serve their respective local community with support for proposal preparation and data reduction, and they will also actively participate in data distribution to principal investigators (PIs) and archive users. In Europe there will be additional centers across the continent that provide their specific expertise to ALMA users, and enhance the ALMA capabilities. In North America there will be one centralized center in Charlottesville, VA, USA, which will provide the same functions for the US and Canada. The structure and location of the Japanese center, which will serve the Asian ALMA community, is not yet officially known. Such a complex network of responsibilities and data requires an archive implementation that is able to cope with complex data access patterns, priorities, and permissions in a flexible and mostly transparent way for the end-users.