Regularized Maximum Likelihood Image Synthesis and Validation for ALMA Continuum Observations of Protoplanetary Disks

Abstract

Regularized Maximum Likelihood (RML) techniques are a class of image synthesis methods that achieve better angular resolution and image fidelity than traditional methods like CLEAN for sub-mm interferometric observations. To identify best practices for RML imaging, we used the GPU-accelerated open source Python package MPoL, a machine learning-based RML approach, to explore the influence of common RML regularizers (maximum entropy, sparsity, total variation, and total squared variation) on images reconstructed from real and synthetic ALMA continuum observations of protoplanetary disks. We tested two different cross-validation (CV) procedures to characterize their performance and determine optimal prior strengths, and found that CV over a coarse grid of regularization strengths easily identifies a range of models with comparably strong predictive power. To evaluate the performance of RML techniques against a ground truth image, we used MPoL on a synthetic protoplanetary disk dataset and found that RML methods successfully resolve structures at fine spatial scales present in the original simulation. We used ALMA DSHARP observations of the protoplanetary disk around HD 143006 to compare the performance of MPoL and CLEAN, finding that RML imaging improved the spatial resolution of the image by up to a factor of 3 without sacrificing sensitivity. We provide general recommendations for building an RML workflow for image synthesis of ALMA protoplanetary disk observations, including effective use of CV. Using these techniques to improve the imaging resolution of protoplanetary disk observations will enable new science, including the detection of protoplanets embedded in disks.

arXiv comment27 pages, 12 figures, accepted for publication in PASP

References in corpus (49)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• Ringed Substructure and a Gap at 1 AU in the Nearest Protoplanetary Disk
• Multi-Scale CLEAN deconvolution of radio synthesis images
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• Dust and Gas in the disc of HL Tauri: Surface density, dust settling, and dust-to-gas ratio
• Observations of gas flows inside a protoplanetary gap
• Kinematic evidence for an embedded protoplanet in a circumstellar disc
• Compressed sensing imaging techniques for radio interferometry
• A Circumplanetary Disk Around PDS70c
• High Resolution Linear Polarimetric Imaging for the Event Horizon Telescope
• Interferometric Imaging Directly with Closure Phases and Closure Amplitudes
• Constraints on the Radial Variation of Grain Growth in the AS 209 Circumstellar Disk
• Imaging the water-snow line during a protostellar outburst
• Imaging the Schwarzschild-radius-scale Structure of M87 with the Event Horizon Telescope using Sparse Modeling
• Sparsity Averaging Reweighted Analysis (SARA): a novel algorithm for radio-interferometric imaging
• GALARIO: a GPU Accelerated Library for Analysing Radio Interferometer Observations
• PURIFY: a new approach to radio-interferometric imaging
• Grain Growth in the Circumstellar Disks of the Young Stars CY Tau and DoAr 25
• The application of compressive sampling to radio astronomy I: Deconvolution
• Millimeter imaging of MWC 758: probing the disk structure and kinematics
• Morphological analysis of the cm-wave continuum in the dark cloud LDN1622
• Super-resolution Full Polarimetric Imaging for Radio Interferometry with Sparse Modeling
• Scale sensitive deconvolution of interferometric images I. Adaptive Scale Pixel (Asp) decomposition
• Dust unveils the formation of a mini-Neptune planet in a protoplanetary ring
• On the Commonality of 10-30AU Sized Axisymmetric Dust Structures in Protoplanetary Disks
• The Disk Substructures at High Angular Resolution Project (DSHARP): X. Multiple rings, a misaligned inner disk, and a bright arc in the disk around the T Tauri star HD 143006
• An inner warp in the DoAr 44 T Tauri transition disk
• Frankenstein: Protoplanetary disc brightness profile reconstruction at sub-beam resolution with a rapid Gaussian process
• Scalable splitting algorithms for big-data interferometric imaging in the SKA era
• Disk Substructures at High Angular Resolution Program (DSHARP): VIII. The Rich Ringed Substructures in the AS 209 Disk
• MORESANE: MOdel REconstruction by Synthesis-ANalysis Estimators. A sparse deconvolution algorithm for radio interferometric imaging
• Molecules with ALMA at Planet-forming Scales (MAPS). A Circumplanetary Disk Candidate in Molecular Line Emission in the AS 209 Disk
• Superresolution Interferometric Imaging with Sparse Modeling Using Total Squared Variation --- Application to Imaging the Black Hole Shadow
• A dusty filament and turbulent CO spirals in HD135344B-SAO206462
• Image reconstruction algorithms in radio interferometry: from handcrafted to learned regularization denoisers
• ALMA observations of Elias 2-24: a protoplanetary disk with multiple gaps in the Ophiuchus Molecular Cloud
• First AI for deep super-resolution wide-field imaging in radio astronomy: unveiling structure in ESO 137--006
• Multi-GPU maximum entropy image synthesis for radio astronomy
• The Millimeter Continuum Size-Frequency Relationship in the UZ Tau E Disk
• Cm-wavelength observations of MWC758: resolved dust trapping in a vortex
• Compressed sensing reconstruction of a string signal from interferometric observations of the cosmic microwave background
• Super-resolution Imaging of the Protoplanetary Disk HD 142527 Using Sparse Modeling
• 3D Detection and Characterisation of ALMA Sources through Deep Learning
• Neural network based image reconstruction with astrophysical priors

Cited by in corpus (4)

• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) II. The radial structure of debris discs
• A young gas giant and hidden substructures in a protoplanetary disk
• exoALMA. VIII. Probabilistic Moment Maps and Data Products using Non-parametric Linear Models
• Seeing the unseen: a method to detect unresolved rings in protoplanetary disks