Selected aspects of the analysis of molecular line observation of edge-on circumbinary disks

TL;DR

This study demonstrates that spatially resolved molecular line observations can effectively reconstruct key structures like cavities and arms in edge-on circumbinary disks, aiding understanding of their inner density distributions.

Contribution

It introduces a method combining hydrodynamic and radiative transfer simulations to assess the observability of inner disk structures in edge-on circumbinary disks.

Findings

Inner cavities and structures can be reconstructed from resolved observations.

Unresolved observations provide limited density gradient estimates.

Feasibility of structure detection depends on observation resolution.

Abstract

Context. Inner cavities, accretion arms and density waves are characteristic structures in the density distribution of circumbinary disks. They are the result of the tidal interaction of the non-axisymmetric gravitational forces of the central binary with the surrounding disk and are most prominent in the inner region, where the asymmetry is most pronounced. Aims. The goal of this study is to test the feasibility of reconstructing the gas density distribution and quantifying properties of structures in the inner regions of edge-on circumbinary disks using multiple molecular line observations. Methods. The density distribution in circumbinary disks is calculated with two-dimensional hydrodynamic simulations. Subsequently, molecular line emission maps are generated with 3D radiative transfer simulations. Based on these, we investigate the observability of characteristic circumbinary structures located in the innermost region for spatially resolved and unresolved disks. Results. We find that it is possible to reconstruct the inner cavity, accretion arms and density waves from spatially resolved multi-wavelength molecular line observation of circumbinary disks seen edge-on. For the spatially unresolved observation only an estimate for the density gradient in the transition area from cavity to inner disk rim can be derived.