Four years of HELAS

The European Coordination Action on HELio- and ASteroseismology (HELAS) has completed its fourth and final year of initial funding by the European Commission. Set up as a network which combines solar and stellar physics communities in the important and vigorously evolving field of seismology, HELAS has been able to coordinate the efforts of European astronomers with remarkable success. Four large international conferences including the HELAS-IV conference on Lanzarote as well as many workshops were organized with a substantial contribution from HELAS. About a dozen workshops, addressing specialized questions in global and local helioseismology and asteroseismology were entirely organized by HELAS. Data analysis tools to prepare the European communities for the upcoming influx of data from new missions have been prepared, tested and demonstrated. Lecture notes and outreach material have been assembled and prepared for general access. As a result, HELAS has an important impact on the scientific output of the astrophysics seismology com-munities and significantly increased the visibility of European research in this field. This paper summarizes the activities and accomplishments of HELAS (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)