J/A+A/627/A16 Silicon K-edge dust absorption cross sections (Zeegers+, 2019)
Dust absorption and scattering in the silicon K-edge.
Zeegers S.T., Costantini E., Rogantini D., de Vries C.P., Mutschke H.,
Mohr P., de Groot F., Tielens. A.G.G.M.
<Astron. Astrophys. 627, A16 (2019)>
=2019A&A...627A..16Z 2019A&A...627A..16Z (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Atomic physics
Keywords: dust, extinction - X-rays: binaries - ISM: abundances
Abstract:
The composition and properties of interstellar silicate dust are not
well understood. Inthe X-rays, interstellar dust can be studied in
detail, by making use of the fine structure features inthe Si K-edge.
The features in the Si K-edge offer a range of possibilities to study
silicon-bearingdust, such as investigating the crystallinity,
abundance and the chemical composition along a given line of sight.
We present newly acquired laboratory measurements of the silicon
K-edge of several silicate-compounds which complement our measurements
from our earlier pilot study. The resulting dust extinction profiles
serve as templates for the interstellar extinction that we observe.
The extinction profiles were used to model the interstellar dust in
the dense environments of the Galaxy.
The laboratory measurements, taken at the Soleil synchrotron facility
in Paris, were adapted for astrophysical data analysis and implemented
in the SPEX spectral fitting program. The models were used to fit the
spectra of nine low-mass X-ray binaries located in the Galactic center
neighborhood in order to determine the dust properties along those
lines of sight.
In most lines of sight can be well fitted by amorphous olivine. We
also established upper limits on the amount of crystalline material
that the modeling allows. We obtained values of the total silicon
abundance, silicon dust abundance and depletion along each of the
sightlines. We find a possible gradient of 0.06±0.02dex/kpc for
the total silicon abundance versus the Galactocentric distance. We do
not find a relation between the depletion and the extinction along the
line of sight.
Description:
We analysed a sample of 14 silicates. Samples 2, 3, 5, 6, 7 and 10
were synthesized for this analysis in laboratories at AIU Jena and
Osaka University. More details about these samples can be found in
this paper and in Zeegers et al. (2017A&A...599A.117Z 2017A&A...599A.117Z). The data
presented in this paper were measured at the Soleil synchrotron
facility in Paris using Lucia beamline. The laboratory absorption
cross-sections of these measurements are given here.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 63 14 Samples
oliv1.dat 27 3001 *Laboratory absorption cross section of olivine,
sample 1, [Mg1.56Fe0.4Si0.91O4]
prox2.dat 27 3001 *Laboratory absorption cross section of pyroxene,
sample 2, [Mg0.9Fe0.1SiO3] amorphous
prox3.dat 27 3001 *Laboratory absorption cross section of pyroxene,
sample 3, [Mg0.9Fe0.1SiO3]
enst4.dat 27 3001 *Laboratory absorption cross section of enstatite,
sample 4, [MgSiO3]
prox5.dat 27 3001 *Laboratory absorption cross section of pyroxene,
sample 5, [Mg0.6Fe0.4SiO3] amorphous
prox6.dat 27 3001 *Laboratory absorption cross section of pyroxene,
sample 6, [Mg0.6Fe0.4SiO3]
oliv7.dat 27 3001 *Laboratory absorption cross section of olivine,
sample 7, [(Mg0.5Fe0.5)2SiO_4] amorphous
prox8.dat 27 3001 *Laboratory absorption cross section of pyroxene,
sample 8, [Mg0.75Fe0.25SiO3]
faya9.dat 27 3001 *Laboratory absorption cross section of fayalite,
sample 9, [Fe2SiO4]
enst10.dat 27 3001 *Laboratory absorption cross section of enstatite,
sample 10, [MgSiO3] amorphous
fors11.dat 27 3001 *Laboratory absorption cross section of forsterite,
sample 11, [Mg2SiO4]
quar12.dat 27 3001 *Laboratory absorption cross section of quartz,
sample 12, [SiO2]
quar13.dat 27 3001 *Laboratory absorption cross section of quartz,
sample 13, [SiO2], amorphous
quar14.dat 27 3001 *Laboratory absorption cross section of quartz,
sample 14, [SiO2], amorphous
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Note on [efopq]*.dat: Header included 3 rows:
- Sample number, corresponding to table 1 in the paper
- Chemical formula and crystallinity
- Column labels
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- No [1/14] Sample identification number
4- 13 A10 --- Name Name
15- 41 A27 --- Chem Chemical formula
43- 51 A9 --- Struct Structure
54- 63 A10 --- Table Name of the table with laboratory absorption
cross section
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Byte-by-byte Description of file (#): [efopq]*.dat
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Bytes Format Units Label Explanations
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2- 10 F9.7 keV E Energy around the Fe K-edge
14- 27 E14.7 Mbarn CR Laboratory absorption cross section
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Acknowledgements:
Sascha Zeegers, szeegers(at)asiaa.sinica.edu.tw
(End) Patricia Vannier [CDS] 03-May-2019