How To Use Thermal Dust Continuum Emission To Measure The Physical Properties Of Dusty Astrophysical Objects

2026/01/16 by Yancy L. Shirley, Jeffrey G. Mangum, Desika Narayanan +1 · 1 voice
Physics and Astronomy · #astro-ph.GA

paper · pdf · doi:10.1088/1538-3873/ae4270

Abstract

Dust grains in the interstellar medium interact with photons across the electromagnetic spectrum. They are generally photon energy converters, absorbing short wavelength radiation and emitting long wavelength radiation. Sixty years ago in 1965, thermal emission from dust grains in the interstellar medium was discovered. This tutorial is a summary of the physics of thermal dust continuum emission and how to use observations of the intensity and flux density of dusty objects to calculate physical properties such as mass, column density, luminosity, dust temperature, and dust opacity spectral index. Equations are derived, when feasible, from first principles with all limits and assumptions explicitly stated. Properties of dust opacities appropriate for different astrophysical environments (e.g. diffuse ISM, dense cores, protoplanetary disks) are discussed and tabulated for the wavelengths of past, current, and future bolometer cameras. Corrections for observations at high redshift as well as the effects of telescope measurement limitations are derived. We also update the calculation of the mean molecular weight in different ISM environments and find that it is 1.404 per H atom, 2.809 per H2 molecule, and 2.351 per gas particle assuming protosolar metallicity and the latest values of the ISM gas phase abundances of metals.

Citations

• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Realistic Multi-temperature Dust: How Well Can We Constrain the Dust Properties of High-redshift Galaxies?
• From small dust to micron-sized aggregates: the influence of structure and composition on the dust optical properties
• Variation of Dense Gas Mass-Luminosity conversion factor with metallicity in the Milky Way
• L1448 IRS3B: Dust Polarization Aligned with Spiral Features, Tracing Gas Flows
• Early Grain Growth in the Young Protostellar Disk HH 212 Supported by Dust Self-Scattering Modeling
• Little evolution of dust emissivity in bright infrared galaxies from 2 < z < 6
• Constraining the gas mass of Herbig disks using CO isotopologues
• Aligned Grains and Scattered Light Found in Gaps of Planet-Forming Disk
• The edge-on protoplanetary disk HH 48 NE II. Modeling ices and silicates
• The chemical make-up of the Sun: A 2020 vision
• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• Observational Constraints on the Physical Properties of Interstellar Dust in the Post-Planck Era
• Dust masses of young disks: constraining the initial solid reservoir for planet formation
• An Analysis of the Shapes of Interstellar Extinction Curves. VII. Milky Way Spectrophotometric Optical-through-Ultraviolet Extinction and Its R-Dependence
• An ALMA survey of the SCUBA-2 CLS UDS field: Physical properties of 707 Sub-millimetre Galaxies
• JINGLE V: Dust properties of nearby galaxies derived from hierarchical Bayesian SED fitting
• The Dust in M31
• L1495 Revisited: A PPMAP View of a Star-Forming Filament
• Discovery of four apparently cold dusty galaxies at z=3.62-5.85 in the COSMOS field: direct evidence of CMB impact on high-redshift galaxy observables
• One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering
• Protoplanetary Disk Masses from Radiative Transfer Modeling: A Case Study in Taurus
• Dust opacity variations in the pre-stellar core L1544
• The Disk Substructures at High Angular Resolution Project (DSHARP): V. Interpreting ALMA maps of protoplanetary disks in terms of a dust model
• CIGALE: a python Code Investigating GALaxy Emission
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Far-infrared to millimeter data of protoplanetary disks: dust growth in the Taurus, Ophiuchus, and Chamaeleon I star-forming regions
• ATLASGAL --- properties of a complete sample of Galactic clumps
• Book Review Interferometry and Synthesis in Radio Astronomy - 3rd Ed
• Multi-temperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
• Parameterizing the interstellar dust temperature
• Dust in the reionization era: ALMA observations of a z=8.38 Galaxy
• Earliest phases of star formation (EPoS): Dust temperature distributions in isolated starless cores
• The physical and chemical structure of Sagittarius B2, I. Three-dimensional thermal dust and free-free continuum modeling on 100 au to 45 pc scales
• Temperature as a third dimension in column-density mapping of dusty astrophysical structures associated with star formation
• Galactic cold cores VI. Dust opacity spectral index
• Inclination-Induced Polarization of Scattered Millimeter Radiation from Protoplanetary Disks: The Case of HL Tau
• Dust evolution in the transition towards the denser ISM: impact on dust temperature, opacity, and spectral index
• Planck 2015 results. XXVIII. The Planck Catalogue of Galactic Cold Clumps
• Can we trace very cold dust from its emission alone ?
• Dusty Star-Forming Galaxies at High Redshift
• Opacity of fluffy dust aggregates
• Reconstructing the density and temperature structure of prestellar cores from Herschel data: A case study for B68 and L1689B
• Astropy: A Community Python Package for Astronomy
• The Bolocam Galactic Plane Survey IX: Data Release 2 and Outer Galaxy Extension
• The degeneracy between dust colour temperature and spectral index. Comparison of methods for estimating the beta(T) relation
• Three-Dimensional Dust Radiative Transfer
• The earliest phases of star formation - A Herschel key project. The thermal structure of low-mass molecular cloud cores
• Far-infrared Spectral Energy Distribution Fitting for Galaxies Near and Far
• The Dust Properties of Bubble HII Regions as seen by Herschel
• The degeneracy between the dust colour temperature and the spectral index. The problem of multiple chi² minima
• HYPERION: An open-source parallelized three-dimensional dust continuum radiative transfer code
• Far-Infrared to Millimeter Astrophysical Dust Emission. II: Comparison of the Two-Level Systems (TLS) model with Astronomical Data
• A dual-frequency sub-arcsecond study of proto-planetary disks at mm wavelengths: first evidence for radial variations of the dust properties
• MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars
• On the Modified Random Walk for Monte-Carlo Radiation Transfer
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from theHerschelGould Belt Survey
• Dust coagulation and fragmentation in molecular clouds. I. How collisions between dust aggregates alter the dust size distribution
• Benchmark problems for continuum radiative transfer. High optical depths, anisotropic scattering, and polarisation
• Radiative transfer in very optically thick circumstellar disks
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Modeling Porous Dust Grains with Ballistic Aggregates I: Geometry and Optical Properties
• Spitzer Power-law AGN Candidates in the Chandra Deep Field-North
• Far-infrared to millimeter astrophysical dust emission I: A model based on physical properties of amorphous solids
• Monte Carlo radiative transfer in protoplanetary disks
• SHARC‐2 350 μm Observations of Distant Submillimeter‐selected Galaxies
• Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective
• Modeling the Physical Structure of the Low Density Pre-protostellar Core Lynds 1498
• Interstellar Grains -- The 75th Anniversary
• A search for evolved dust in Herbig Ae stars
• Interstellar Dust Grains
• The Degree of CO Depletion in Pre-stellar Cores
• Physical structure and CO abundance of low-mass protostellar envelopes
• The dust temperature distribution in prestellar cores
• Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer
• Accretion Disks around Young Objects. III. Grain Growth
• Tracing the Mass during Low‐Mass Star Formation. IV. Observations and Modeling of the Submillimeter Continuum Emission from Class I Protostars
• Tracing the Mass during Low-Mass Star Formation. II. Modelling the Submillimeter Emission from Pre-Protostellar Cores
• Submillimeter Imaging of the Luminous Infrared Galaxy Pair VV 114
• Infrared cirrus - New components of the extended infrared emission
• The size distribution of interstellar grains
• Evolutionary Signatures in the Formation of Low‐Mass Protostars
• Tracing the Mass during Low‐Mass Star Formation. III. Models of the Submillimeter Dust Continuum Emission from Class 0 Protostars
• Tracing the Mass during Low-Mass Star Formation. I. Submillimeter Continuum Observations
• Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. I. Dielektrizitätskonstanten und Leitfähigkeiten der Mischkörper aus isotropen Substanzen
• Beiträge zur Optik trüber Medien, speziell kolloidaler Metallösungen

Discussions

• Largely driven by and based on Yancy Shirley's years of teaching graduate students about the wonders of thermal dust continuum emission as a tool for measuring astrophysical objects. A @paspjournal.bs [bsky, 0 points, 0 comments]

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