Globular clusters of the Gaia Enceladus/Sausage I. Orbital and dynamical evolution on cosmological timescales
Bilodid M. Ishchenko M. Berczik P.
1 December 2025EDP Sciences
Astronomy and Astrophysics
2025#704
Context. The history of our Galaxy is shaped by significant merger events, which contribute to its mass and to the distribution of stars, but which also bring globular clusters that act as the main tracers of the accretion history of the Milky Way. Aims. We investigated Gaia-Enceladus/Sausage globular cluster samples and studied their orbital and dynamical evolution over cosmological timescales in external time-variable potential. We estimated the limits of distribution of the escaped stars from the globular clusters’ orbital evolution in energy angular momentum space. Methods. To reconstruct the orbital evolution of the known globular clusters of the dwarf galaxy Gaia-Enceladus/Sausage, we used the parallel N-body code φ-GPU. We investigated the relationship between globular clusters and their progenitor by analysing their orbital parameters and phase-space distribution during 9 Gyr of evolution in the past. We created a N-body model of Gaia-Enceladus/Sausage globular clusters and analysed their dynamical evolution and distribution of the escaped stars today. Results. We summarised the samples of the Gaia-Enceladus/Sausage globular clusters and created two main categories: ‘most probable’ and ‘tentative’, with 15 and 9 clusters, respectively. We analysed the evolution of their kinematic, orbital, and phase-space parameters in the external time-variable potential. We defined phase-space distribution limits of stars that escape from globular clusters during 9 Gyr of evolution: a specific energy from −18 to −12.2 ×104 km2 s−2, Lz from −0.98 to 0.72 ×103 kpc km s−1, and Lperp from 0 to 1.8 ×103 kpc km s−1. The limits of the GE/S debris in Galactic area based on orbital parameters of the GC’s escaped stars are: for apocentre and pericetre distances of 10–28 and 1–4 kpc, <18 kpc in Galactocentric radius and <|15| kpc in the Z direction. Generally we compared the phase-space distribution of escaped stars from the GCs GE/S debris energy-angular momentum limits with the observed very metal-poor stars, which belong to the GE/S itself and produce consistent results.
galaxies: individual: Gaia-Enceladus/Sausage , globular clusters: general , methods: numerical
Text of the article Перейти на текст статьи
Main Astronomical Observatory, National Academy of Sciences of Ukraine, 27 Akademika Zabolotnoho St, Kyiv, 03143, Ukraine
Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, ul. Bartycka 18, Warsaw, 00-716, Poland
Fesenkov Astrophysical Institute, Observatory 23, Almaty, 050020, Kazakhstan
Space Technology and Space Law Research Center, Szechenyi Istvan University, Egyetem ter 1, Gyor, 9026, Hungary
Main Astronomical Observatory
Nicolaus Copernicus Astronomical Centre
Fesenkov Astrophysical Institute
Space Technology and Space Law Research Center
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026