Abstract
A model for the formation of superdense gaseous cores by accretion in the nuclei of disk galaxies has been proposed. Equations for radial flow of gas into the nucleus in the presence of aweak galactic magnetic field have been solved, and time scales for the accretion of an exploding mass in the nucleus (∼109 M ⊙) have been obtained under several different situations in the absence of any rotation. The time scales are found to lie in the range between a few times 107 yr and 108 yr. Such time scales have been proposed by some authors for repeated explosions in the nuclei of galaxies; they have also proposed that spiral arms in disk galaxies are repeatedly formed and destroyed over such time scales. It is shown that the presence of rotational velocities in the infalling gas practically destroys the efficiency of the accretion process unless such velocities are dissipated by frictional forces within the system. Viscosity of gas is the most obvious dissipative agent. The problem of accretion of a rotating viscous gas will be discussed in a subsequent paper.
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Basu, B., Bhattacharyya, T. On the formation of superdense gaseous cores in the nuclei of disk galaxies — I. Astrophys Space Sci 70, 263–279 (1980). https://doi.org/10.1007/BF00639556
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DOI: https://doi.org/10.1007/BF00639556