Recovering the structure of debris disks non-parametrically from images

TL;DR

This paper introduces an extended non-parametric algorithm for reconstructing the structure of debris disks from images at all inclinations, enabling detailed analysis of their radial and vertical profiles.

Contribution

The authors adapt the rave algorithm for all disk inclinations, allowing non-parametric recovery of disk structures from images, with validation on simulated and real ALMA data.

Findings

Accurate recovery of disk features larger than the PSF size.

Radial and vertical structures largely agree with existing methods.

Observed trends in disk properties with age and stellar temperature.

Abstract

Debris disks common around Sun-like stars carry dynamical imprints in their structure that are key to understanding the formation and evolution history of planetary systems. In this paper, we extend an algorithm (rave) originally developed to model edge-on disks to be applicable to disks at all inclinations. The updated algorithm allows for non-parametric recovery of the underlying (i.e., deconvolved) radial profile and vertical height of optically thin, axisymmetric disks imaged in either thermal emission or scattered light. Application to simulated images demonstrates that the de-projection and deconvolution performance allows for accurate recovery of features comparable to or larger than the beam or PSF size, with realistic uncertainties that are independent of model assumptions. We apply our method to recover the radial profile and vertical height of a sample of 18 inclined debris disks observed with ALMA. Our recovered structures largely agree with those fitted with an alternative visibility-space de-projection and deconvolution method (frank). We find that for disks in the sample with a well-defined main belt, the belt radius, fractional width and fractional outer edge width all tend to increase with age, but do not correlate in a clear or monotonic way with dust mass or stellar temperature. In contrast, the scale height aspect ratio does not strongly correlate with age, but broadly increases with stellar temperature. These trends could reflect a combination of intrinsic collisional evolution in the disk and the interaction of perturbing planets with the disk's own gravity.