J/A+A/627/A51 Levels and rate coefficients of the Fe-L (Gu+, 2019)
X-ray spectra of the Fe-L complex.
Gu L., Raassen A.J.J., Mao J., de Plaa J., Shah C., Pinto C., Werner N.,
Simionescu A., Mernier F., Kaastra J.S.
<Astron. Astrophys. 627, A51 (2019)>
=2019A&A...627A..51G 2019A&A...627A..51G (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Excitation rates
Keywords: atomic data - atomic process - techniques: spectroscopic -
galaxies: clusters: intracluster medium
Abstract:
A major challenge in X-ray spectral modeling is the Fe-L spectrum,
which is basically a complex assembly of n≥3 to n=2 transitions of Fe
ions in different ionization states, affected by a range of atomic
processes such as collisional excitation, resonant excitation,
radiative recombination, dielectronic recombination, and innershell
ionization. In this paper we perform a large-scale theoretical
calculation on each of the processes with the flexible atomic code
(FAC), focusing on ions of FeXVII to FeXXIV that form the main body
of the Fe-L complex. The calculation includes a large set of energy
levels with a broad range of quantum number n and l, taking into
account the full-order configuration interaction and all possible
resonant channels between two neighboring ions. The new data are found
to agree within 20% with the recent individual R-matrix calculations
for the main FeL lines, although the discrepancies become
significantly larger for the weaker transitions, in particular for
FeXVIII, FeXIX, and FeXX. By further testing the new FAC
calculations with the high-quality RGS data from 15 elliptical
galaxies and galaxy clusters, we note that the new model gives
systematically better fits than the current SPEX v3.04 code, and the
mean Fe abundance decreases by 12%, while the O/Fe ratio increases by
16% compared with the results from the current code. Comparing the FAC
fit results to those with the $R$-matrix calculations, we find a
temperature-dependent discrepancy of up to 10% on the Fe abundance
between the two theoretical models. Further dedicated tests with both
observed spectra and targeted laboratory measurements are needed to
resolve the discrepancies, and ultimately to get the atomic data ready
for the next high-resolution X-ray spectroscopy mission.
Description:
Level-resolved and energy-dependent rate coefficients for the X-ray
transitions in the Fe-L shell (Ne-like to Li-like) in collisional
ionization equilibrium. The calculation was done with the flexible
atomic code (FAC). The rate coefficients of direct collisional
excitation, resonant excitation, radiative recombination, and
dielectronic recombination are presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 60 4261 Atomic levels (only excited states are listed)
table2.dat 108 21305 Rate coefficients
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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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2- 5 I4 --- Index Level number
7- 8 I2 --- Z Atomic number
10- 11 I2 --- Ion Isoelectronic sequence number
13- 14 I2 --- n Principle quantum number
16- 17 I2 --- L Angular momentum quantum number
19- 20 I2 --- 2S+1 Spin quantum number
22- 23 I2 --- 2J Twice the total angular momentum quantum number
25- 48 A24 --- Config Level non-relativistic configuration
51- 60 E10.5 keV Energy Energies of excited states relative to ground
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Ion Isoelectronic sequence number
5- 8 I4 --- Index Level index as given in Table 1
10- 12 F3.1 keV kT Temperature in equilibrium
15- 24 E10.5 s-1 CE Rate coefficient of direct collisional
excitation from the ground without cascade
27- 36 E10.5 s-1 RE Rate coefficient of resonant excitation from
the ground without cascade
39- 48 E10.5 s-1 REc Rate coefficient of resonant excitation from
the ground including cascade
51- 60 E10.5 s-1 RRc Rate coefficient of radiative recombination
including cascade
63- 72 E10.5 s-1 DRc Rate coefficient of dielectronic recombination
including cascade
75- 84 E10.5 s-1 CE+RE1 Rate coefficient of direct+resonant excitation
from level 1 without cascade
87- 96 E10.5 s-1 CE+RE2 Rate coefficient of direct+resonant excitation
from level 2 without cascade
99-108 E10.5 s-1 CE+RE3 Rate coefficient of direct+resonant excitation
from level 3 without cascade
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Acknowledgements:
Liyi Gu, l.gu(at)sron.nl
(End) Liyi Gu [RIKEN], Patricia Vannier [CDS] 05-Jun-2019