Evidence of dust grain evolution from extinction mapping in the IC 63 photodissociation region

Abstract

Photodissociation regions (PDRs) are parts of the ISM consisting of predominantly neutral gas, located at the interface between H II regions and molecular clouds. The physical conditions within these regions show variations on very short spatial scales, and therefore PDRs constitute ideal laboratories for investigating the properties and evolution of dust grains. We have mapped IC 63 at high resolution from the UV to the NIR (275 nm to 1.6 $\mu$m), using the Hubble Space Telescope WFC3. Using a Bayesian SED fitting tool, we simultaneously derive a set of stellar ($T_{\text{eff}}$, $\log (g)$, distance) and extinction ($A_V$, $R_V$) parameters for 520 background stars. We present maps of $A_V$ and $R_V$ with a resolution of 25 arcsec based on these results. The extinction properties vary across the PDR, with values for $A_V$ between 0.5 and 1.4 mag, and a decreasing trend in $R_V$, going from 3.7 at the front of the nebula to values as low as 2.5 further in. This provides evidence for evolution of the dust optical properties. We fit two modified blackbodies to the MIR and FIR SED, obtained by combining the $A_V$ map with data from Spitzer and Herschel. We derive effective temperatures (30 K and 227 K) and the ratio of opacities at 160 $\mu$m to V band ${\kappa }_{160}/{\kappa }_V$ ($7.0\times 10^{-4}$ and $2.9\times 10^{-9}$) for the two dust populations. Similar fits to individual pixels show spatial variations of ${\kappa }_{160}/{\kappa }_V$. The analysis of our HST data, combined with these Spitzer and Herschel data, provides the first panchromatic view of dust within a PDR.

arXiv comment28 pages, 20 figures, accepted for publication in The Astrophysical Journal

References in corpus (55)

• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• Correcting for the Effects of Interstellar Extinction
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• Interstellar Dust Grains
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• WFPC2 Stellar Photometry with HSTphot
• Drizzle: A Method for the Linear Reconstruction of Undersampled Images
• A Grid of NLTE Line-Blanketed Model Atmospheres of O-type Stars
• Gaia Data Release 2: using Gaia parallaxes
• Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains
• The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• New Interstellar Dust Models Consistent with Extinction, Emission, and Abundance Constraints
• Photoelectric Emission from Interstellar Dust: Grain Charging and Gas Heating
• The global dust SED: Tracing the nature and evolution of dust with DustEM
• The Panchromatic Hubble Andromeda Treasury
• Toward High-Precision Astrometry with WFPC2. I. Deriving an Accurate PSF
• The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
• The global dust modelling framework THEMIS (The Heterogeneous dust Evolution Model for Interstellar Solids)
• The Panchromatic Hubble Andromeda Treasury X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars
• The Effect of Line of Sight Temperature Variation and Noise on Dust Continuum Observations
• Analysis of the emission of very small dust particles from Spitzer spectro-imagery data using blind signal separation methods
• Inverse temperature dependence of the dust submillimeter spectral index
• Three-Dimensional Dust Radiative Transfer
• The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2)
• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
• The Effect of Noise on the Dust Temperature - Spectral Index Correlation
• Evaporating Very Small Grains as tracers of the UV radiation field in Photo-dissociation Regions
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Dust variations in the diffuse interstellar medium: constraints on Milky Way dust from Planck-HFI observations
• Evolution of dust in the Orion Bar with Herschel: I. Radiative transfer modelling
• The Panchromatic Hubble Andromeda Treasury XV. The BEAST: Bayesian Extinction and Stellar Tool
• Excitation of H${}_2$ in photodissociation regions as seen by Spitzer
• The degeneracy between the dust colour temperature and the spectral index. The problem of multiple chi^2 minima
• Dust processing in photodissociation regions - Mid-IR emission modelling
• The Orion HII Region and the Orion Bar in the Mid-Infrared
• Spitzer Mapping of PAHs and H2 in Photodissociation Regions
• A Dust spectral energy distribution model with hierarchical Bayesian inference. I. Formalism & benchmarking
• Mapping the Extinction Curve in 3D: Structure on Kiloparsec Scales
• Red Giant evolution and specific problems
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. I. Overview and Initial Results
• SMC-Type Interstellar Dust in the Milky Way
• The Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE): The Dust Extinction Curve from Red Clump Stars
• Physical structure of the photodissociation regions in NGC 7023. Observations of gas and dust emission with Herschel

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• A Panchromatic Study of Massive Stars in the Extremely Metal-Poor Local Group Dwarf Galaxy Leo A
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• Far-ultraviolet Dust Extinction and Molecular Hydrogen in the Diffuse Milky Way Interstellar Medium
• The origin of dust polarization in the Orion Bar
• Influence of the nano-grain depletion in photon-dominated regions: Application to the gas physics and chemistry in the Horsehead
• High Resolution Observations of HI in the IC 63 Reflection Nebula
• The Local Ultraviolet to Infrared Treasury I. Survey Overview of the Broadband Imaging