J/A+A/670/A115 Dark dust II programs (Siebenmorgen, 2023)
Dark dust II. Properties in the general field of the diffuse ISM.
Siebenmorgen R.
<Astron. Astrophys., 670, A115 (2023)>
=2023A&A...670A.115S 2023A&A...670A.115S (SIMBAD/NED BibCode)
ADC_Keywords: Models
Keywords: dust, extinction - polarization - infrared: ISM - stars: distances
Abstract:
Distance estimates derived from spectroscopy or parallax have been
unified by considering extinction by large grains. The addition of
such a population of what is called dark dust to models of the diffuse
interstellar medium is tested against a contemporary set of
observational constraints. By respecting representative solid-phase
element abundances, the dark dust model simultaneously explains the
typical wavelength-dependent reddening, extinction, and emission of
polarised and unpolarised light by interstellar dust particles between
far-UV and millimeter wavelengths. The physical properties of dark
dust were derived. Dark dust consists of micrometer-sized particles.
These particles have recently been detected in situ. Dark dust
provides significant wavelength-independent reddening from the far-UV
to the near-infrared. Light absorbed by dark dust is re-emitted in the
submillimeter region by grains at dust temperatures of 8-12K. This
very cold dust has frequently been observed in external galaxies. Dark
dust contributes to the polarisation at ≳1mm to ∼35% and marginally
at shorter wavelengths. Optical constants for silicate dust analogous
were investigated. By mixing 3% in mass of Mg0.8Fe0.22+ SiO3 to
MgO-0.5 SiO2, a good fit to the data was derived that can still
accommodate up to 5-10% of mass in dark dust. The additional diming
of light by dark dust is unexplored when supernova Ia light curves are
discussed and in other research. Previous models that ignored dark
dust do not account for the unification of the distance scales.
Description:
Run and plot results of dark dust model.
jsmDD.f:
Fortran code for computing dust cross sections and emission spectrum
for ISRF heating, Parameter files are changed in Input/jsmDD.inp.
pl_sedarkISM.pro:
creates pl_sedarkISM.pdf with Fig detailed in the paper.
RUN:
gfortran -ffixed-line-length-132 crossec_dd.f -o a.crossec_dd
./a.jsmDD
then use IDL 8.8.2 (darwin x86_64 m64) and type:
idl istart.pro
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
alias.pro 79 151 alias.pro file
istart.pro 45 17 istart.pro file
jsm.com 98 50 jsm.com file
jsmDD.f 132 3172 jsmDD.f file
pl_sedarkISM.pdf 512 446 pl_sedarkISM figure
pl_sedarkISM.pro 121 1078 pl_sedarkISM.pro file
ISMsedata.xdr 512 6 ISMsedata.xdr file
AAstron/* . 729 AAstron files
Coyote/* . 311 Coyote files
Data/* . 8 Data files
Input/* . 11 Input files
Output/* . 7 Output files
OutputCopy/* . 7 OutputCopy files
files.tar 512 15518 All files in a tar file
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Acknowledgements:
Ralf Siebenmorgen, rsiebenm(at)eso.org
References:
Siebenmorgen, Paper I 2023A&A...670A.115S 2023A&A...670A.115S
Siebenmorgen et al., Paper III 2023A&A...676A.132S 2023A&A...676A.132S
(End) Patricia Vannier [CDS] 05-Dec-2023