Description du projet
Mesurer la véritable échelle de distance de l’univers
Les déterminations les plus récentes de la vitesse actuelle d’expansion de l’univers, exprimée par la fameuse constante de Hubble, présentent une différence considérable avec la valeur déduite des observations du fond diffus cosmologique par le satellite européen Planck. Le projet UniverScale, financé par l’UE, se concentrera sur l’estimation des distances aux galaxies très lointaines, considérées par les astronomes comme l’univers primitif. Les chercheurs calibreront deux méthodes géométriques qui mesureront des distances beaucoup plus grandes que celles incluses dans les publications de données de Gaia. Leur approche éliminera les erreurs systématiques présentes dans d’autres méthodes de mesure. Les résultats du projet auront des implications importantes pour l’astrophysique moderne, en particulier dans notre compréhension de l’énigmatique énergie noire.
Objectif
After detection of the accelerated expansion of the Universe (Nobel prize 2011) and the existence of an enigmatic “dark energy” component of the matter-energy content of the Universe the physical explanation of the nature of dark energy has become a major challenge for astronomers and physicists in recent years. The recent empirical determinations of H0 complicated even more our understanding of the Universe since they differ by about 4σ from the value obtained from Planck data and the ΛCDM model, which suggest that new physics might be required in the models.
We will calibrate two geometrical methods which will yield 1% distances a thousand times further out than Gaia parallaxes. The great advantage of our approach is the full control on all potential errors affecting the distance determinations, including systematic errors elusive in most other methods. In addition, we will provide mutual crosschecks at the sub-percent accuracy level with three completely independent geometrical methods. This will allow for the first time to verify the accuracy (and not only precision) at this unprecedented level of precision. Applying these methods we will calibrate the extragalactic distance scale with an unprecedented precision and accuracy. This will allow for a 1% H0 determination with Cepheids and SN Ia. Novel reverberation studies of AGN continua will allow us to determine H0 completely independently, and provide direct insight into the larger redshift Universe, including the H(z) dependence which will constrain other cosmological parameters.
Our results will have strong impact on many fields of modern astrophysics. In particular they will definitively answer the question if new physics beyond the standard cosmological model is required. They will also be central to understand the physical nature of dark energy which constitutes about 72% of the matter-energy of the Universe.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-SyG - Synergy grantInstitution d’accueil
00-716 Warszawa
Pologne