BEGIN:VCALENDAR VERSION:2.0 PRODID:-//ZContent.net//ZapCalLib 1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT DTSTART;TZID=Atlantic/Canary:20221201T103000 DTEND;TZID=Atlantic/Canary:20221201T113000 UID:iactalks-1640 X-WR-CALNAME: IAC Talks: Open Astronomy Seminars X-ORIGINAL-URL: /iactalks/Talks/view/1640 CREATED:2022-12-01T10:30:00+00:00 X-WR-CALDESC: IAC Talks upcomming talks SUMMARY:Open questions on bar pattern speed with the Tremaine-Weinberg meth od DESCRIPTION:Open questions on bar pattern speed with the Tremaine-Weinberg method\nDr. Virginia Cuomo\n\nBars are prominent features observed in most disc galaxies, having a crucial\nrole in the secular evolution of their h osts. Indeed, they redistribute material within the galaxies, while rotati ng around the centre at a given angular frequency, the bar pattern speed. When formed in an isolated galaxy, a bar is expected to be born as fast ro tating with a bar rotation rate R (a parameter used to describe the bar pa ttern speed) equal to 1.0 ≤ R ≤ 1.4. During its evolution, the bar c an be slowed through the exchange of angular momentum with the other compo nents and/or when an efficient dynamical friction is exerted by the dark m atter (DM) halo. In this case, R is shifted in the slow regime (R > 1.4 ), while the bar radius and strength are increasing. On the other hand, ul trafast (UF) bars, with R < 1.0, are physically unstable. Measuring the bar rotation rate becomes desirable both to investigate the secular evolu tion of barred galaxies and to test whether the measured DM distribution m atches that predicted by cosmological simulations in the cold DM framework . The only model-independent way to recover the bar pattern speed (and der ive R) is the Tremaine-Weinberg (TW) method, nowadays largely applied than ks to the advent of integral-field spectroscopy: most of the analysed bars are compatible with the fast regime, while a non-negligible fraction belo ngs to the unstable UF regime. As a consequence, the question arises wheth er these results are biased by an improper application of the method or in stead they come from a not completely theoretically understanding of the n ature of slow/UF bars.We explore the open questions on bar pattern speed w ith the TW method by1. testing the reliability of the TW measurements whic h led to UF bars2. pushing further the quest of slow bars applying the TW method to a sample of dwarf galaxies, the best candidates to host slowly-r otating bars, since they arecommonly thought to host a massive and central ly-concentrated DM halo.We measure the bar radius from the analysis of the maps tracing the transverse-to-radial force ratio, showing that UF bars a re no longer observed when the correct measurement of the bar radius is ad opted to derive R. We apply the TW method to dedicated MUSE observations o f a sample of 5 dwarf barred\ngalaxies from the Virgo cluster, showing tha t the analysed bars are slowly-rotating. This suggests they could have bee n slowed down by a dense and massive DM halo.\n--------------------------- ------------------------------------\nZoom: \nhttps://rediris.zoom.us /j/88520341620?pwd=RldDYzFzeU8zYzlOckozbjloUmEwZz09\nMeeting ID: 885 2034 1620 Passcode: 818629 \n \nYouTube: https://you tu.be/8yLu_LHWuxc END:VEVENT END:VCALENDAR