Local fragmentation of thin discs in Eddington-inspired gravity. Issue 1 (21st June 2018)

• Record Type: Journal Article
• Authors: Roshan, Mahmood; Kazemi, Ali; De Martino, Ivan
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 479:Issue 1(2018)
• Page Start: 1287
• Page End: 1296
• Publication Date: 2018-06-21
• Subjects: gravitation -- hydrodynamics -- instabilities; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty1647
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We find the generalized version of the Toomre's criterion for the stability of a rotating thin disc in the context of Eddington-inspired Born-Infeld (EiBI) gravity that possesses one free parameter χ. 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 disc. Finally, we find a new version of Toomre's stability criterion for thin discs. We show that EiBI gravity with negative χ destabilizes all the rotating thin discs. On the other hand, EiBI with positive χ substantially can suppress the local fragmentation, and has stabilizing effects against axisymmetric perturbations. More specifically, we show that only an annulus remains unstable on the surface of the disc. The width of the annulus directly depends on the magnitude of χ.