Angular Momentum and Horn's Problem

Galactic Disk Formation and the Angular Momentum Problem

Galactic disk formation requires knowledge about the initial conditions under which disk galaxies form, the boundary conditions that affect their secular evolution and the micro-physical processes that drive the multi-phase interstellar medium and regulate their star formation history. Most of these ingredients are still poorly understood. Recent high-resolution observations of young high-redsh...

Angular Momentum

Rotations and Angular Momentum

2 Exercise. Prove it. ◦ In fact, as sophisticates can show you, on a complex space a linear operator which preserves all norms will also preserve all inner products. But the key thing is to remember is that a unitary operator preserves all inner products (and therefore all norms). • This is analogous to the fact that translations and rotations in ordinary three-dimensional space preserve distan...

Rotation and Angular Momentum

There is a fundamental connection between the angular momentum (a mechanical quantity) and the rotation operators (which is a symmetry group). The angular momentum is the generator of rotations. Because of this connection, many properties of angular momentum operators can be derived from the properties of the rotation group. We will derive these properties (mainly the commutation relations) sta...

The Cosmological Angular Momentum Problem of Low-Mass Disk Galaxies

The rotational properties of the visible and dark components of low-mass disk galaxies (vrot ≤ 100 km/s) are investigated using the Swaters sample. The rotational parameter λ = λ(jd/md) is determined, where λ is the dark halo spin parameter and jd/md is the ratio between the specific angular momentum of the disk and that of the dark halo. The distribution of λ is in excellent agreement with cos...