Fakultät für Physik und Astronomie
STEPHEN PHILLIPS hostreviews.co.uk / UNSPLASH

Dark matter and angular momentum in nearby disc galaxies

Pavel Mancera Pina , Leiden Observatory

Dark matter and angular momentum are key parameters regulating the evolution of galaxies through cosmic time: they largely control their total mass, size, and morphology. During the last years, we have exploited exquisite observations and state-of-the-art analysis tools to robustly measure the motions of the cold gas in disc galaxies, which in turn allows us to infer their dark matter and angular momentum. This talk will be divided into three main parts. In the first part, I will focus on the startling dynamics of gas-rich ultra-diffuse galaxies (UDGs). UDGs are very peculiar systems: they have similar effective radii as big spirals like the Milky Way but about 1000 times fewer stars, making them very diffuse. By carefully modelling their gas kinematics, we found that our galaxies rotate much slower than other galaxies with similar baryonic mass, making them strong outliers of the baryonic Tully-Fisher relation. Moreover, our UDGs have baryon fractions as high as the cosmological average, and they appear to have dark matter distributions challenging to explain in the Cold Dark Matter model. In the second part of the talk, I will present some of the most detailed measurements of the baryonic specific angular momentum of nearby disc galaxies to date. We discovered a new relationship between the baryonic mass, baryonic specific angular momentum, and gas content; this is one of the tightest known scaling relations of disc galaxies. Finally, in the last part of the talk, I will show our recent and accurate determinations of the dark matter content in a sample of nearby galaxies. For the first time, we systematically accounted for the fact that their gaseous discs are not razor-thin but thick and flared, which allowed us to obtain some of the most detailed estimations of the dark matter content in nearby galaxies. We also revisited baryonic and dark matter scaling relations, finding evidence of feedback processes imprinting signatures on them.

ARI Institute Colloquium
17 Nov 2022, 11:15
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG

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