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arXiv · 1806.07414

Local fragmentation of thin disks in Eddington-inspired gravity

Mahmood Roshan·Ali Kazemi·Ivan De Martino
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Abstract

We find the generalized version of the Toomre's criterion for the stability of a rotating thin disk in the context of Eddington inspired Born-Infeld (EiBI) gravity which possesses one free parameter $\chi$. To do so we use the weak field limit of the theory and find the dispersion relation for the propagation of matter density waves on the surface of a self-gravitating and differentially rotating disk. Finally we find a new version of Toomre's stability criterion for thin disks. We show that EiBI gravity with negative $\chi$ destabilizes all the rotating thin disks. On the other hand EiBI with positive $\chi$ substantially can suppress the local fragmentation, and has stabilizing effects against axi-symmetric perturbations. More specifically, we show that only an annulus remains unstable on the surface of the disk. The width of the annulus directly depends on the magnitude of $\chi$.

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Mahmood Roshan, Ali Kazemi, Ivan De Martino. 2018-06-19. Local fragmentation of thin disks in Eddington-inspired gravity. https://doi.org/10.1093/mnras%2Fsty1647

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