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X-WR-CALNAME:Osservatorio Astrofisico di Catania
X-ORIGINAL-URL:https://www.oact.inaf.it
X-WR-CALDESC:Eventi per Osservatorio Astrofisico di Catania
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DTSTART:20250101T000000
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DTSTART;TZID=UTC:20250929T110000
DTEND;TZID=UTC:20250929T120000
DTSTAMP:20260404T145147
CREATED:20250915T101627Z
LAST-MODIFIED:20250927T182741Z
UID:18701-1759143600-1759147200@www.oact.inaf.it
SUMMARY:The Fossil Groups puzzle: ancient relics or young pretenders?
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE: Monday\, September 29\, 11:00 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Stefano Zarattini (Centro de Estudios de Física del Cosmos de Aragón – CEFCA) \nABSTRACT:Fossil groups (FGs) were initially believed to represent the end stage of galaxy group evolution\, characterised by a significant luminosity gap between their two brightest member galaxies which was seen as an indicator of their advanced age. In this picture\, FGs were thought to undergo a long passive evolution in which their bright satellites gradually merged into the central galaxy\, making them fossil relics of the ancient Universe. However\, results from the Fossil Group Origins (FOGO) project suggest a paradigm shift: FGs are not necessarily old\, but rather isolated systems whose location within the cosmic web primarily regulates their evolution. In this scenario\, the magnitude gap arises at low redshift thanks to the infall of galaxies on radial orbits\, which enhances the merging rate observed in FGs. \nIn this seminar\, I will review the progress achieved over the last 15 years that led to this new interpretation. I will discuss the luminosity functions\, substructures\, cosmic web environment\, and orbital distribution of FG galaxies\, also highlighting the view of FGs as transitional systems. Numerical simulations will also be presented to support the observational evidence\, reinforcing the idea that the magnitude gap is a relatively recent feature rather than the imprint of an early formation epoch. \n  \nA few rules:— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/the-fossil-groups-puzzle-ancient-relics-or-young-pretenders/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
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