Marina Ishchenko (Academy of Sciences, Ukraine)
Context. To date, two main mechanisms have been proposed for the formation and growth of nuclear star clusters (NSCs) in galaxies. The first suggests in situ star formation from gas that has migrated to the central regions from the galaxy’s outskirts, while the second involves the accretion of stars from disrupted globular clusters (GCs) onto the galactic centre. However, the relative importance of these mechanisms in the evolution of NSCs across different galaxy morphologies remains an open question. Aims. To investigate the accretion of GC stars on early cosmological timescales through detailed N-body simulations of theoretical GC models, in order to assess the role of this mechanism in Milky Way-like galaxies. Methods. For the dynamical modelling, we use the updated parallel N-body code φ-GPU including stellar evolution. We prepared three sets of GC models with different half-mass radii (rhm), each consisting of 50 full N-body GC models, and integrated these models in an external, time-variable Milky Way-like potential taken from the cosmological database IllustrisTNG-100. The simulations cover the time interval from -10 Gyr to -5 Gyr, enabling us to assess the rate of early stellar accretion onto the proto-NSC. Results. GC models with average orbital eccentricities of 0.4–0.5 and orbits oriented perpendicular to the galactic disc contribute most significantly to the mass of the proto-NSC formation. Accretion is especially efficient during the first Gyr and in compact GC models with rhm = 1 pc. In all sets, the dominant accreted stellar population consists of low-mass stars (≈0.33 M⊙). However, the accreted mass alone is insufficient to fully account for the current mass of the NSC. Conclusions. Based on our extended set of numerical simulations, we obtain the lower limit of mass contribution (≈ 2%) to the NSC from disrupted GCs. We conclude that the GC stellar accretion channel alone may not be sufficient to ensure the present day MW galaxy NSC mass budget
Chandra Sekhar Saraf (Korea Astronomy and Space Science Institute)
Abbas Askar (CAMK PAN, Warsaw)
Since 2015, the detection of more than 200 gravitational-wave mergers of compact-object binaries has been announced by the LIGO–Virgo–KAGRA collaboration, opening a new observational window onto the Universe and providing detailed information on the demographics of compact objects, in particular black holes. Yet, the astrophysical origin of these sources remains an open question. In this talk, I will review the main proposed formation pathways for compact-object mergers, including isolated binary evolution and various dynamical channels. I will focus in particular on the dynamical formation of gravitational-wave sources in dense stellar environments such as star clusters and galactic nuclei, highlighting their characteristic signatures, expected rates, and how future observations may help us distinguish between different formation scenarios.
Maciej Zgirski (Institute of Physics, PAN,, Warsaw)
Maciej Zgirski Leader of the CoolPhon Group at MAGTOP at the Institute of Physics, Polish Academy of Sciences (IF PAN) - http://coolphongroup.ifpan.edu.pl/ zgirski@ifpan.edu.pl, +48730003175 Short CV: Maciej Zgirski (born 1979) graduated from the Faculty of Physics of Warsaw University of Technology in 2003. Defended his PhD in the field of the experimental low temperature mesoscopic physics at the University of Jyväskylä, Finland in 2008. In years 2008-2010 he joined Quantronics Group (CEA) in Saclay, France as a PostDoc. Since end of 2010 employed at the Institute of Physics, PAN in Warsaw. Since 06/2024 professor at the International Centre for Interfacing Magnetism and Superconductivity with Topological Matter (MAGTOP) at the Institute of Physics. Received habilitation in 2022 for the creation of the pioneering time-resolved low- temperature thermometry and its application for the experimental investigation of the dynamical thermal processes at the nanoscale. Specializing in thermodynamics of nanostructures with the emphasis on the fast thermometry based on the various types of superconducting Josephson junctions. Another his expertise involves building novel-concept superconducting devices based on manipulating just a single superconducting vortex. The experimental approaches, sample designs, and measuring protocols used in the CoolPhon Group are of pioneering character, and create a backbone for new applications in the field of applied mesoscopic superconductivity.
Arthur Puls (CAMK, Warsaw)
winter break
winter break
CAMK Annual Meeting
