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Evidence of dust grain evolution from extinction mapping in the IC 63 photodissociation region
- Source :
- ASTROPHYSICAL JOURNAL, The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2020, 888 (1), pp.22. ⟨10.3847/1538-4357/ab557f⟩
- Publication Year :
- 2020
-
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.<br />Comment: 28 pages, 20 figures, accepted for publication in The Astrophysical Journal
- Subjects :
- 010504 meteorology & atmospheric sciences
Opacity
INFRARED-EMISSION
ULTRAVIOLET
CHEMICAL-STRUCTURE
FOS: Physical sciences
Astrophysics
Photodissociation region
ALPHA ABSORPTION
01 natural sciences
INTERSTELLAR H-I
IC-63 NEBULA
0103 physical sciences
SMALL-MAGELLANIC-CLOUD
010303 astronomy & astrophysics
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
Physics
Nebula
Molecular cloud
Astronomy and Astrophysics
Astrophysics - Astrophysics of Galaxies
Interstellar medium
Stars
OPTICAL EXTINCTION
Physics and Astronomy
[SDU]Sciences of the Universe [physics]
13. Climate action
Space and Planetary Science
Extinction (optical mineralogy)
Astrophysics of Galaxies (astro-ph.GA)
X-RAY-ABSORPTION
BLANKETED MODEL ATMOSPHERES
Small Magellanic Cloud
Subjects
Details
- Language :
- English
- ISSN :
- 15384357 and 0004637X
- Database :
- OpenAIRE
- Journal :
- ASTROPHYSICAL JOURNAL, The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2020, 888 (1), pp.22. ⟨10.3847/1538-4357/ab557f⟩
- Accession number :
- edsair.doi.dedup.....dc521335c68688dbba4da51560442e02