Audrey TrovaHuré; Hersant20 min

Vertical self-gravity in discs and outer edge effects

For massive enough or/and extended gaseous disks, self-gravity is important and can partly govern hydrostatic equilibrium. According to Paczynski's approximation (Paczynski 1978), the vertical gravity field is a linear function of the surface density. This approximation, often used in the context of star formation and accretion in Active Galactic Nuclei, clearly fails in zones where gradients of density and thickness are noticeable (typically discs edges). By analytical means, we have estimated the vertical component caused by a vertically homogeneous disc (in integral and algebraic forms) with an accuracy better than 1%. At zeroth order, Paczynski's approximation can be corrected (i.e. Extended) and the new formula depends on the relative distance to the outer edge and the local disc thickness. We will present this two results which are interesting to better understand the impact of self gravity on the hydrostatic equilibrium and to better model the outer disc where most observations come from.