Relatore
Descrizione
The dual role of RR Lyrae (RRL) stars as tracers of ancient merging events and high-precision distance indicators is fundamental to investigating the evolutionary history of the Milky Way (MW). Their distribution in the Galactic Halo and Globular Clusters provides a unique opportunity to trace interactions with satellite galaxies. This study investigates the origin of the Oosterhoff dichotomy, specifically focusing on whether it is an intrinsic feature of the Galaxy or was "imported" through merging events with dwarf galaxies, such as Gaia-Enceladus and Sagittarius. To test this hypothesis, we apply chemo-dynamic classifications to a large sample of RRLs, analyzing their distribution in the space of integrals of motion to distinguish between in situ and accreted populations. Accurate orbital analysis is ensured by the derivation of a new Period-Wesenheit-Metallicity (PWZ) relation, using a robust Bayesian MCMC (Markov Chain Monte Carlo) framework combined with Gaia astrometric data. Preliminary results show that the PWZ coefficients are consistent with current literature. This framework sets the stage for a detailed characterization of the pulsational properties (including Fourier parameters) for each identified dynamical component, aiming to reconstruct the early assembly of our Galaxy with high precision.
| Sessione | La Galassia e il Gruppo Locale |
|---|