Oscar Agertz
Associate Professor / Senior university lecturer / Wallenberg Academy Fellow
The specific angular momentum of disc galaxies and its connection with galaxy morphology, bar structure, and disc gravitational instability
Author
Summary, in English
The specific angular momenta (j J/M) of stars (j∗), gas (jgas), baryons as a whole (jb) and dark matter haloes (jh) contain clues of vital importance about how galaxies form and evolve. Using one of the largest samples of disc galaxies (S0-BCD) with high-quality rotation curves and near-infrared surface photometry, we perform a detailed comparative analysis of j that stretches across a variety of galaxy properties. Our analysis imposes tight constraints on the 'retained' fractions of specific angular momentum (j∗/jh, jH i/jh, and jb/jh), as well as on their systematic trends with mass fraction and galaxy morphology, thus on how well specific angular momentum is conserved in the process of disc galaxy formation and evolution. In particular, one of the most innovative results of our analysis is the finding that galaxies with larger baryon fractions have also retained larger fractions of their specific angular momentum. Furthermore, our analysis demonstrates how challenging it is to characterize barred galaxies from a gravitational instability point of view. This is true not only for the popular Efstathiou, Lake & Negroponte bar instability criterion, which fails to separate barred from non-barred galaxies in about 55 per cent of the cases, but also for the mass-weighted Toomre parameter of atomic gas, <QHi>, which succeeds in separating barred from non-barred galaxies, but only in a statistical sense.
Department/s
- Lund Observatory - Has been reorganised
- eSSENCE: The e-Science Collaboration
- Astrophysics
Publishing year
2023-01-01
Language
English
Pages
1002-1021
Publication/Series
Monthly Notices of the Royal Astronomical Society
Volume
518
Issue
1
Document type
Journal article
Publisher
Oxford University Press
Topic
- Astronomy, Astrophysics and Cosmology
Keywords
- galaxies: fundamental parameters
- galaxies: haloes
- galaxies: ISM
- galaxies: kinematics and dynamics
- galaxies: stellar content
- instabilities
Status
Published
ISBN/ISSN/Other
- ISSN: 0035-8711