The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here:

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Oscar Agertz. Profile photo.

Oscar Agertz

Associate Professor / Senior university lecturer / Wallenberg Academy Fellow

Oscar Agertz. Profile photo.

The specific angular momentum of disc galaxies and its connection with galaxy morphology, bar structure, and disc gravitational instability


  • Alessandro B. Romeo
  • Oscar Agertz
  • Florent Renaud

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.


  • Lund Observatory - Has been reorganised
  • eSSENCE: The e-Science Collaboration
  • Astrophysics

Publishing year







Monthly Notices of the Royal Astronomical Society





Document type

Journal article


Oxford University Press


  • Astronomy, Astrophysics and Cosmology


  • galaxies: fundamental parameters
  • galaxies: haloes
  • galaxies: ISM
  • galaxies: kinematics and dynamics
  • galaxies: stellar content
  • instabilities




  • ISSN: 0035-8711