Séminaire/Seminar Galaxies |
| « Early onset of the hot circumgalactic medium around Milky Way galaxies » |
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Victor Rufo Pastor |
| Hot coronae are key to Milky Way (MW)-type galaxy formation and are commonly thought to emerge when dark matter haloes reach Mvir ~ 10^12 M?, allowing accretion shocks to heat gas to virial temperatures. Using the VINTERGATAN cosmological simulation suite, we investigate the roles of stellar feedback and accretion shocks in establishing the circumgalactic medium (CGM) of MW-mass galaxies. We find that stellar feedback drives the early formation of a hot CGM with TCGM ~ Tvir, whereas accretion shocks alone fail to produce similarly high temperatures at z > 2, independent of gas metallicity. With feedback, CGM virialisation and a hot corona (T > 10^5 K) can emerge as early as z ˜ 3 at Rvir, much earlier than in feedback-free models (z ? 1). Feedback also changes virialisation from the inside-out evolution expected from accretion shocks to a rapid (? 0.5 Gyr), outside-in or nearly simultaneous transition. These early coronae remain largely stable to the present day, while their apparent evolution can result from the time-dependent definition of Rvir, a ‘CGM pseudo-evolution’ analogous to that of dark matter haloes. |
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jeudi 8 octobre 2026 - 11:00 Salle 281 Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |