The SpaceInn Board

The European Helio- and Asteroseismology Network (HELAS) has initiated the follow-up project "SpaceInn - Exploitation of Space Data for Innovative Helio- and Asteroseismolgoy" with the mission to build on the existing European strength in the field of time-domain stellar physics. SpaceInn activities, which are organized around the themes of data access, scientific expertise and existing coordination, aim to secure optimal use of the existing and planned data, from space and from the ground, in helio- and asteroseismology. Starting in January 1, 2013, the SpaceInn project is funded for four years by the European Union.

Laurent Gizon (MPS), John G. Beck (Stanford)

In time-distance helioseismology wave travel times are measured from the cross-correlation between Doppler velocities recorded at any two locations on the solar surface. All local helioseismology inferences rely critically on the definition of travel time and its accuracy. We compare two different methods to extract the travel times from the noisy cross-correlation functions. The first method consists of fitting a 5-parameter analytic function to the cross-correlation to obtain the phase travel time. The second method consists of linearizing the distance between the observed cross-correlation and a sliding reference cross-correlation (the only parameter is the travel time). We find that the one-parameter fits are more robust with respect to noise. Using SOHO data from the MDI Structure Program for the years 1996–2003, we study in detail the statistical properties of the noise associated with the travel-time measurements for the two different fitting methods.

The HELAS Board

The objective of the European Helio- and Asteroseismology Network (HELAS) is to coordinate the activities of the European activities in helio- and asteroseismology. HELAS was funded as Coordination Action under the European Union's Framework Programme 6 (FP6) from April 2006 - March 2010. Since then the network continued its activities. The poster here is the original HELAS poster from the year 2006. At that time HELAS had 10 European partners. Since 2010 the consortium has grown and comprises now 24 partners with two partners from the USA. The new website of the project can be found at: http://www.helas-project.eu

The HELAS Board

HELAS had the major objective to bring together the widely dispersed European research groups active in helio- and asteroseismology. The transfer of knowledge and data analysis techniques through HELAS lead to a structuring of this field of research, as it was needed to prepare the European research community for important missions as the space missions Solar Dynamics Observatory (SDO), Kepler, CoRoT, and Picard. Here we summarize the achievements of HELAS.