Leda Berni (INAF- Osservatorio Astrofisico di Arcetri (Florence, Italy))
The Λ-CDM scenario predicts that the Milky Way assembled hierarchically, through the accretion of smaller systems such as globular clusters and dwarf galaxies. Although these systems can be disrupted by tidal interactions, their remnants survive as stellar streams that retain chemical and dynamical signatures of common origin. We developed CREEK, a machine-learning pipeline that learns similarity relations between stars using siamese neural networks, models their relational structure with graph neural networks autoencoders, and identifies substructures through density-based clustering (OPTICS). Applied to halo stars, our method recovers 80% of known globular clusters in the dataset, re-identifies established stellar streams, and reveals a candidate new substructure. We also detect two distinct populations within the Gaia Enceladus stream, possibly linked to multiple accretion passages through the Milky Way. The CREEK thus represents an objective and data-driven method for the selection of stars belonging to streams and to stellar structures in general, and the results highlight the capabilities of machine learning to find relations that would escape a classical search.
Martin Solar (Adam Mickiewicz University, Poznań)
Core-collapse supernovae are very energetic explosions that have a significant impact in the interstellar medium within galaxies. However, it is not well understood how progenitors of core-collapse supernovae form, evolve, and explode. In this talk, I plan to constrain the core-collapse supernova progenitor properties studying their star formation efficiency (or molecular gas depletion time) environments. In summary, it is found that interacting massive binaries occur in regions of intense, efficient star formation rather than simply higher gas content.
Dominika Król (Harvard Smithonian CfA)
Maciek Wielgus (Instituto de Astrofísica de Andalucía, IAA-CSIC, Granada, Hiszpania)
Laetitia Gibaud (Department of Physics, University of Białystok)
Samik Mitra (Astrophysics and Relativity Group International Centre for Theoretical Sciences, Bengaluru, India)
