A comment on the viscous stability of relativistic Keplerian accretion disks

Recently, Ghosh reported a new regime of instability in Keplerian accretion disks that is caused by relativistic effects. This instability appears in the gas pressure-dominated region when all relativistic corrections to the disk structure equations are taken into account. We show that he uses the s tability criterion incorrectly, leading to inappropriate conclusions. We pe rform a standard stability analysis to show that no unstable region exists when the relativistic disk is gas pressure dominated.