Magnetic braking as a solution to the angular momentum problem of ellptical galaxies

Abstract

The following idea is explored in this thesis: the angular momentum problem of elliptical galaxies can be solved by invoking magnetic braking operating during the formative phases of protoelliptical galaxies. For reducing significantly the angular momentum of a Jeans unstable object by magnetic braking, it is necessary that the object takes longer than a free-fall time to collapse. The possibility of a “slow” collapse for protogalaxies is examined and worked out. Giant Molecular Complexes (GMCs) have been observed to live for time scales that are longer than their free-fall time scales. Using the expressions developed for the analysis of slow collapses of protogalaxies, we examine the energetics of the collapse of GMCs and their substructure.