Changes Of Dust Opacity With Density in the Orion A Molecular Cloud

Abstract

We have studied the opacity of dust grains at submillimeter wavelengths by estimating the optical depth from imaging at 160, 250, 350, and 500 um from the Herschel Gould Belt Survey and comparing this to a column density obtained from the 2MASS-derived color excess E(J-Ks). Our main goal was to investigate the spatial variations of the opacity due to "big" grains over a variety of environmental conditions and thereby quantify how emission properties of the dust change with column (and volume) density. The central and southern areas of the Orion A molecular cloud examined here, with NH ranging from 1.5X10^21 cm^-2 to 50X10^21 cm^-2, are well suited to this approach. We fit the multi-frequency Herschel spectral energy distributions (SEDs) of each pixel with a modified blackbody to obtain the temperature, T, and optical depth, τ(1200), at a fiducial frequency of 1200 GHz (250 um). Using a calibration of NH/E(J-Ks)for the interstellar medium (ISM) we obtained the opacity (dust emission cross-section per H nucleon), σ_e(1200), for every pixel. From a value of ~ 1X10^-25 cm^2 H^-1 at the lowest column densities that is typical of the high latitude diffuse ISM, σ_e(1200) increases as NH^0.28 over the range studied. This is suggestive of grain evolution. Integrating the SEDs over frequency, we also calculated the specific power P (emission power per H) for the big grains. In low column density regions where dust clouds are optically thin to the interstellar radiation field (ISRF), P is typically 3.7 X 10^-31 W H^-1, again close to that in the high latitude diffuse ISM. However, we find evidence for a decrease of P in high column density regions, which would be a natural outcome of attenuation of the ISRF that heats the grains, and for localized increases for dust illuminated by nearby stars or embedded protostars.

13 pages, 11 Figures, To appear in the Astrophysical Journal

References in corpus (3)

• The spine of the swan: A Herschel study of the DR21 ridge and filaments in Cygnus X
• The Structure of Molecular Clouds: I - All Sky Near Infrared Extinction Maps
• Estimating distance, pressure, and dust opacity using submillimeter observations of self-gravitating filaments

Cited by in corpus (85)

• Planck 2013 results. XI. All-sky model of thermal dust emission
• What determines the density structure of molecular clouds ? A case study of Orion B with Herschel
• Characterizing the properties of nearby molecular filaments observed with Herschel
• Planck intermediate results. XVII. Emission of dust in the diffuse interstellar medium from the far-infrared to microwave frequencies
• Reconstructing the density and temperature structure of prestellar cores from $Herschel$ data: A case study for B68 and L1689B
• Formation and evolution of interstellar filaments; Hints from velocity dispersion measurements
• Modelling Dust Evolution in Galaxies with a Multiphase, Inhomogeneous ISM
• The Herschel and JCMT Gould Belt Surveys: Constraining Dust Properties in the Perseus B1 Clump with PACS, SPIRE, and SCUBA-2
• Class 0 Protostars in the Perseus Molecular Cloud: A Correlation Between the Youngest Protostars and the Dense Gas Distribution
• Two Mass Distributions in the L 1641 Molecular Clouds: The Herschel connection of Dense Cores and Filaments in Orion A
• Planck intermediate results. XXXIII. Signature of the magnetic field geometry of interstellar filaments in dust polarization maps
• Variation in dust properties in a dense filament of the Taurus molecular complex (L1506)
• Planck intermediate results. XXI. Comparison of polarized thermal emission from Galactic dust at 353 GHz with interstellar polarization in the visible
• The Panchromatic Hubble Andromeda Treasury VIII: A Wide-Area, High-Resolution Map of Dust Extinction in M31
• Detection of two power-law tails in the probability distribution functions of massive GMCs
• The CARMA-NRO Orion Survey
• Understanding star formation in molecular clouds II. Signatures of gravitational collapse of IRDCs
• Optically thick HI dominant in the local interstellar medium; an alternative interpretation to "dark gas"
• Cosmic rays, gas and dust in nearby anticentre clouds : I -- CO-to-H2 conversion factors and dust opacities
• Galactic cold cores V. Dust opacity
• The optical properties of dust: the effects of composition, size, and structure
• Grain alignment and disruption by radiative torques in dense molecular clouds and implication for polarization holes
• Mantle formation, coagulation and the origin of cloud/core-shine: II. Comparison with observations
• Cloud Structure of Galactic OB Cluster Forming Regions from Combining Ground and Space Based Bolometric Observations
• Understanding star formation in molecular clouds IV. Column density PDFs from quiescent to massive molecular clouds
• An X-rays Survey of the Young Stellar Population of the Lynds 1641 and Iota Orionis Regions
• JCMT POL-2 and BISTRO Survey observations of magnetic fields in the L1689 molecular cloud
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars
• An ALMA study of hub-filament systems I. On the clump mass concentration within the most massive cores
• A Dust spectral energy distribution model with hierarchical Bayesian inference. I. Formalism & benchmarking
• Dust Emissivity in the Star-Forming Filament OMC 2/3
• Optically thick HI does not dominate dark gas in the local ISM
• A detailed study of the interstellar protons toward the TeV $\gamma$-ray SNR RX J0852.0$-$4622 (G266.2$-$1.2, Vela Jr.); a third case of the $\gamma$-rays and ISM spatial correspondence
• HI, CO, and Dust in the Perseus Cloud
• Filaments in the Lupus molecular clouds
• Planck intermediate results. XXVIII. Interstellar gas and dust in the Chamaeleon clouds as seen by Fermi LAT and Planck
• Dust spectrum and polarisation at 850 um in the massive IRDC G035.39-00.33
• Young stellar clusters in the Rosette molecular cloud. Arguments against triggered star formation
• Gravitationally unstable condensations revealed by ALMA in the TUKH122 prestellar core in the Orion A cloud
• Herschel and SCUBA-2 observations of dust emission in a sample of Planck cold clumps
• Synthetic Observations of 21cm HI Line Profiles from Inhomogeneous Turbulent Interstellar HI Gas with Magnetic Field
• Probing the cold magnetized Universe with SPICA-POL (B-BOP)
• Multiwavelength study of the high-latitude cloud L1642: chain of star formation
• Determination of the far-infrared dust opacity in a prestellar core
• Scattering from dust in molecular clouds: Constraining the dust grain size distribution through near-infrared cloudshine and infrared coreshine
• Velocity structure of the 50 pc-long NGC 6334 filamentary cloud: Hints of multiple compressions and their impact on the cloud properties?
• Possible Evidence for Cosmic-Ray Acceleration in the Type Ia SNR RCW 86: Spatial Correlation between TeV Gamma rays and Interstellar Atomic Protons
• Dust evolution across the Horsehead Nebula
• Probing the structure of a massive filament: ArTeMiS 350 and 450 micron mapping of the integral-shaped filament in Orion A
• Galactic cold cores IX. Column density structures and radiative transfer modelling
• Molecular cloud catalogue from ${}^{13}$CO(1-0) data of the Forgotten Quadrant Survey
• Herschel Observations of the W3 GMC (II): Clues to the Formation of Clusters of High-Mass Stars
• Cosmic-rays, gas, and dust in nearby anti-centre clouds : III -- Dust extinction, emission, and grain properties
• Globules and Pillars in Cygnus X I. Herschel Far-infrared imaging of the Cyg OB2 environment
• Galactic Cold Cores VII: Filament Formation and Evolution - Methods & Observational Constraints
• The turbulent life of dust grains in the supernova-driven, multi-phase interstellar medium
• Fermi-LAT gamma-ray study of the interstellar medium and cosmic rays in the Chamaeleon Molecular-Cloud Complex: A look at the dark gas as optically thick HI
• A new method for probing magnetic field strengths from striations in the interstellar medium
• Gas and Dust Properties in the Chamaeleon Molecular Cloud Complex based on the Optically Thick HI
• Joint Modelling of Dust Scattering and Thermal Emission: The Spider Complex
• Spatially associated clump populations in Rosette from CO and dust maps
• Thermal Starless Ammonia Core Surrounded by CCS in the Orion A Cloud
• Interstellar extinction in Orion. Variation of the strength of the UV bump across the complex
• Molecular and Atomic Clouds Associated with the Gamma-Ray Supernova Remnant Puppis A
• TIMES I: a Systematic Observation in Multiple Molecular Lines Toward the Orion A and Ophiuchus Clouds
• Element Stratification in the Middle-Aged Type Ia Supernova Remnant G344.7-0.1
• A submillimeter search for pre- and proto-brown dwarfs in Chamaeleon II
• Magnetic Field of Molecular Gas Measured with the Velocity Gradient Technique I. Orion A
• The Distribution of UV Radiation Field in the Molecular Clouds of Gould Belt
• Mapping of interstellar clouds with infrared light scattered from dust: TMC-1N
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Synthetic observations of dust emission and polarisation of Galactic cold clumps
• Dust emission, extinction, and scattering in LDN 1642
• Filaments in the OMC-3 cloud and uncertainties in estimates of filament profiles
• The Effelsberg survey of FU Orionis and EX Lupi objects I. -- Host environments of FUors/EXors traced by NH${}_3$
• The JCMT Gould Belt Survey Complete Core Catalogue: Core mass function variations between nearby molecular clouds
• On the possible correlation of Galactic VHE source locations and enhancements of the surface density in the Galactic plane
• Study of the Cosmic Rays and Interstellar Medium in Local HI Clouds using Fermi-LAT Gamma-Ray Observations
• Dust evolution: going beyond the empirical
• Cosmic rays, gas and dust in the Central Molecular Zone I -- $X_{CO}$ factors, cosmic-ray densities and dust opacities
• Modelling of dust emission of a filament in the Taurus molecular cloud
• Dust emission and extinction in the Orion OMC-3 cloud
• Dense Molecular Ring-like structure in gaseous CO depletion region G34.74-0.12
• On volume density and star formation in nearby molecular clouds
• Effect of dust rotational disruption by radiative torques on radiation pressure feedback from massive protostars