The Science of ET – Blue book published on arXiv, with large German contribution
26.05.2025
With the Blue Book, members of the ET Collaboration present a comprehensive discussion of ET´s science objectives, providing state-of-the-art predictions for the capabilities of ET in both geometries currently under consideration, a single site triangular configuration or two L-shaped detectors.
The Blue Book is a milestone paper of the ET Collaboration and a major deliverable of the European ET-PP project. Nearly 200 key contributors have worked on this comprehensive ~600-page study, the result of dedicated efforts by the ET Collaboration´s Observational Science Board, coordinated by Marica Branchesi, Archisman Gosh and Michele Maggiore.
The authors discuss
- the impact that ET will have on domains as broad and diverse as fundamental physics, cosmology, early Universe, astrophysics of compact objects, physics of matter in extreme conditions, and dynamics of stellar collapse.
- how the study of extreme astrophysical events will be enhanced by multi-messenger observations.
- the ET synergies with ground-based and space-borne GW observatories, including multi-band investigations of the same sources, improved parameter estimation, and complementary information on astrophysical or cosmological mechanisms obtained combining observations from different frequency bands.
- advancements in waveform modeling dedicated to third-generation observatories, along with open tools developed within the ET Collaboration for assessing the scientific potentials of different detector configurations.
- the data analysis challenges posed by third-generation observatories, which will enable access to large populations of sources and provide unprecedented precision.