General Seminar
current | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017
General Seminar takes place every Monday at 11.15 in Piwnice, radioastronomy seminar room.
Remote participation via the BigBlueButton (BBB).
9 December 2024
“Cluster winds and how they depend on the stellar population parameters”
mgr Hanno Stinshoff (Institute of Astronomy, Nicolaus Copernicus University)
Abstract:
Young massive clusters (YMCs) are affected in their evolution by the feedback of their stars, which makes massive stars with high mass loss an important contributor. Under certain conditions the collective winds of the stars (resulting in the cluster wind) form dense, warm clumps, that can provide a starting place for a second generation of stars, that inherits abundances of the first generation. This is then observed later in globular clusters (GCs) as abundance anomalies. This scenario hinges on many factors like the amount of mass available for the second generation (the so-called mass budget) and the cluster wind power. To investigate this, I varied the cluster wind velocity prescriptions for synthetic populations to see the consequences. This way the conditions for winds that result in the formation of a second generation can be outlined. For this I am showing the results of a semi-analytic code solving spherically symmetric hydrodynamic equations describing the star cluster wind and second stellar generations (“WINDCALC”, Wünsch et al., 2017). I applied it to the “BoOST” stellar evolution model grids from Szécsi et al. (2022) to ensure a broad range of stellar parameters as basis for the population.
16 December 2024
“4MOST: the 4-metre Multi-Object Spectroscopic Telescope”
prof. dr hab. Boud Roukema (Institute of Astronomy, Nicolaus Copernicus University)
Abstract:
4MOST — the 4-m Multi-Object Spectroscopy Telescope project is an astronomical survey instrument that is currently undergoing commissioning on the ESO VISTA telescope at Paranal. With 2436 optical fibres and a 4.2 square degree field of view, 4MOST will carry out simultaneous stellar spectroscopic surveys of the Milky Way and extragalactic redshift surveys covering substantial fractions of the past light cone. 4MOST expects to obtain spectra for 25 million objects over 15000 square degrees during the first 5-year period. This includes 10 4MOST Consortium Surveys (70% of the observing time ) and 15 Community Surveys (30% of the observing time). An overview of the instrument and the galactic (Milky Way halo, bulge, and disk; Magellanic Clouds) and extragalactic (galaxy clusters, AGNs, galaxy evolution, cosmological redshifts, time-variable objects) surveys will be presented.