High-Energy Astrophysics has entered a new era, with a number of operational and near-future instruments being deployed in space, and a large X-ray observatory, Athena, being built for a launch around the end of next decade. These facilities play a fundamental role in the new venue of Multimessenger astronomy, as shown by the ground breaking discovery of the electromagnetic counterparts to the gravitational wave event GW170817 observed by LIGO/Virgo  (Fig.1) or to the neutrino source TXS 0506+056.

AHEAD2020 is perfectly positioned in time and scope to successfully address such unique opportunities for the high-energy and multimessenger astronomical communities. The aim of this proposal is to bring together on European scale, and open up facilities for a) testing both ground and space-based technologies in an environment representative of space conditions, b) exploiting data, and c) computational modelling. We want to  ensure to European researchers, from both academia and industry, the opportunities of joint technological development and optimal access and use of observational resources and data. The reference communities will get further integrated throughout a strong networking activity and the observing infrastructures advanced by focused joint research activities. AHEAD2020 builds on the results achieved by the previous AHEAD (H2020) project and on the advanced degree of coordination and networking reached so far by the involved communities. It aims at further integrating the high energy astrophysical community within its own and with the multimessenger community, to exploit successfully the multimessenger window. In order to foster the creation of a European multi-messenger astrophysics platform, AHEAD2020 brings in activities encompassing gravitational wave, electromagnetic wave and neutrinos, with the goal of developing a wider multi-disciplinary community and foster a better exploitation of the multimessenger results. Technology and analysis tools focus on strengthening the performance and utilization of present and future facilities, to prepare the community to make the most of the unprecedented capabilities deployed by e.g. Athena or to experiments for transient and multimessenger searches based on novel technology. AHEAD2020 fits timely in the exciting science and the cutting-edge technology that will be developed in the next years making them ripe for the benefit of the industrial market and the European society. AHEAD2020 will address the following key objectives:

  • Integrate and coordinate national activities in high-energy astrophysics at a much higher level than it is presently available within Europe, and extending such effort by bringing in multimessenger activities. AHEAD2020 involves 38 participants from 16 countries, including major European institutions in the field and 4 SMEs, and it offers to users 30 facilities for instrument tests, data analysis and computational astrophysics/multimessenger modelling, including one virtual access for gravitational and multimessenger data.  AHEAD2020 aims at bringing the high-energy astrophysical and multimessenger community to an advanced level of integration by strongly focusing on networking and standardization, and by establishing common access procedures to facilities. Such effort of integration relies on the progress achieved with AHEAD but also on the strong links already in place between the high energy, gravitational and neutrino communities, as demonstrated by the recent discoveries in the field.
  • Provide a network of ground-based test facilities for developing, calibrating and testing both generic technologies as well as instruments developed for space missions in an environment representative of space conditions. Experience gained with AHEAD allows us to identify and concentrate the offer on the most requested facilities, while broadening the scope of the access with new services and the inclusion of training visits. This network will ensure that European scientists, engineers and SMEs have more opportunities to access some of the most advanced infrastructures for space environmental testing of components and instrument characterization. Access will be provided in particular to scientists and engineers without national access to similar facilities. For this objective, AHEAD will offer 9 installation facilities that can accomodate 36 different projects, and can serve 105 users, offering a total access of 150 days.
  • Push the limits of current technology, develop the appropriate tools and strengthen the infrastructure needed for maximizing the scientific return of new future high energy and multimessenger facilties, such as Athena, satellites for the transient and multimessenger Universe (nanosat, Theseus, Einstein Probe), neutrino and GW observatories (KM3NET, Einstein Telescope).  Beyond the state-of-the-art, we will focus on specific  development of technology, tools and techniques for these experiments (X-ray collecting optics and calibration, development detectors and handling of the in orbit background, laboratory astrophysics and atomic data base and new tools for high spectral resolution, advanced tools for transient monitoring of the sky, pilot studies and tools for new multimessenger facilties). This will be realized by bringing scientists from 16 different countries together in a joint research program.
  • Ensure maximal scientific return from present and near future observing facilities in the field of high energy and multimessengerastronomy (including XMM, INTEGRAL, Fermi, Chandra, Einstein Probe, SVOM, VIRGO, LIGO, VHE and neutrino observatories)  by making accessible and usable multimessenger  data, developing data analysis and theory tools specifically dedicated to multimessenger data exploitation, and also offering access to a network of expert research infrastructures in data analysis and computational astrophysics as well as virtual access to GW data.. Access will be provided in particular to teams in Europe and Associated Countries who currently have no strong expertise in data analysis.  For this objective, AHEAD offers access to 20 facilities that can accommodate 148 different projects and users, offering a total access of 770 days.

Figure 1. The power of multimessenger astronomy. Discovery of the electromagnetic counterparts of GW170817. Upper panel shows the sequence of observations of the various emission components and their origin at the source during and after the merging of two neutron stars. Lower panel. The prompt signal observed in GW antennas and gamma-rays (Fermi and Integral) is show on the left (Abbott et al, 2017, ApJ 848, L13), in the center the optical counterpart produced by the kilonova as observed by HST and on the right the X-ray afterglow produced by the jet as observed by Chandra (Troja, Piro, van Eerten et al 2017, Nature 551, 71).

  • Promote high-energy and multimessengerastrophysics at various levels (e.g., regional, national, European, international) and in different communities (scientists, teachers, and public). Prepare communities in less experienced countries to participate in the high energy and multimessenger science.
  • Prepare the community to the scientific exploitation of the new facilities under development in Europe in high energy and multimessengerastrophysics bytraining the next generation of young researchers in the field.Combine knowledges of European scientists and leading European industrial partners enabling technological transfer for the development of innovative technologies for the benefit of the European society and the high-tech industrial market.