Published November 9, 2018 | Version v1
Conference paper Open

New Perspectives on Galactic Angular Momentum, Galaxy Formation, and the Hubble Sequence

  • 1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
  • 2. Dept. of Physics & Astronomy, San Jose State University, One Washington Square, San Jose, CA 95192, USA


This paper provides a summary of our recent work on the scaling relations between the specific angular momentum $j_{\star}$ and mass $M_{\star}$ of the stellar parts of normal galaxies of different bulge fraction $\beta_{\star}$. We find that the observations are consistent with a simple model based on a linear superposition of disks and bulges that follow separate scaling relations of the form $j_{\star{\rm d}} \propto M_{\star{\rm d}}^{\alpha}$ and $j_{\star{\rm b}} \propto M_{\star{\rm b}}^{\alpha}$ with $\alpha = 0.67 \pm 0.07$ but offset from each other by a factor of $8 \pm 2$ over the mass range $8.9 \leq \log (M_{\star}/M_{\odot}) \leq 11.8$. This model correctly predicts that galaxies follow a curved 2D surface in the 3D space of $\log j_{\star}$, $\log M_{\star}$, and $\beta_\star$.



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