BEGIN:VCALENDAR VERSION:2.0 PRODID:-//https://astronomia.uc.cl/2jucext1/institutoastrofisica///NONSGML kigkonsult.se iCalcreator 2.10.15// METHOD:PUBLISH BEGIN:VEVENT UID:20260518T185732-04-7363JIu3t6@https://astronomia.uc.cl/2jucext1/institu toastrofisica/ DTSTAMP:20260518T225732Z DESCRIPTION:Do dark-matter-deficient dwarf galaxies present a challenge to the LCDM paradigm?\nSugata Kaviraj\nUniversity of Hertfordshire\n \;\n In the standard LCDM paradigm\, dwarf galaxies are expected to be dark mat ter-rich\, as baryonic feedback is thought to quickly drive gas out of the ir shallow potential wells and quench star formation at early epochs. Rece nt observations of local dwarfs with extremely low dark matter content app ear to contradict this picture\, potentially bringing the validity of the standard model into question. We use New Horizon\, a high-resolution cosmo logical simulation\, to demonstrate that sustained stripping of dark matte r\, in tidal interactions between a massive galaxy and a dwarf satellite\, naturally produces dwarfs that are dark matter-deficient\, even though th eir initial dark matter fractions are normal. The process of dark matter s tripping is responsible for the large scatter in the halo-to-stellar mass relation in the dwarf regime. The degree of stripping is driven by the clo seness of the orbit of the dwarf around its massive companion and\, in ext reme cases\, produces dwarfs with halo-to-stellar mass ratios as low as un ity\, consistent with the findings of recent observational studies. ~30 pe r cent of dwarfs show some deviation from normal dark matter fractions due to dark matter stripping\, with 10 per cent showing high levels of dark m atter deficiency (M_halo/M_?<\; 10). Given their close orbits\, a signif icant fraction of dark matter-deficient dwarfs merge with their massive co mpanions (e.g. ~70 per cent merge over time-scales of ~3.5 Gyr)\, with the dark matter-deficient population being constantly replenished by new inte ractions between dwarfs and massive companions. The creation of these gala xies is therefore a natural by-product of galaxy evolution and their exist ence is not in tension with the standard paradigm.\n \; https://astron omia.uc.cl/2jucext1/institutoastrofisica/en/instituto/coloquios/event/491- do-dark-matter-deficient-dwarf-galaxies-present-a-challenge-to-the-lcdm-pa radigm-sugata-kaviraj DTSTART:20211026T183000Z DTEND:20211026T193000Z LOCATION:Santiago Chile () SUMMARY:Do dark-matter-deficient dwarf galaxies present a challenge to the LCDM paradigm? - Sugata Kaviraj URL:https://astronomia.uc.cl/2jucext1/institutoastrofisica/en/instituto/col oquios/event/491-do-dark-matter-deficient-dwarf-galaxies-present-a-challen ge-to-the-lcdm-paradigm-sugata-kaviraj END:VEVENT END:VCALENDAR