Transcript The Iron-Line Complex - RHESSI Measurements Brian Dennis

The Iron-Line Complex
RHESSI Measurements
Brian Dennis David Smith
Ken Phillips
Richard Schwartz
Hugh Hudson Kim Tolbert
RHESSI Workshop
4 – 6 June, 2003
5/24/2016 8:07 PM
Glasgow, Scotland
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RHESSI Spectra
• RHESSI sees the iron-line complex at
~6.7 keV even with the thin and thick
shutters in.
• The peak energy can be determined to
<0.1 keV.
• The equivalent width (or line-to-continuum
ratio) can also be accurately determined.
• The iron/nickel line complex at ~8 keV can
also be detected.
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Shutters Out
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RHESSI
Spectra
Thin Shutters
In (A1)
Detector #4
1-minute
accumulations
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RHESSI
Spectra
Thin Shutters (A1)
Thin + Thick (A3)
Detector #4
1-minute
accumulations
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RHESSI Spectra
Spectra in Thin (A1) & Thin+Thick (A3) Shutter States
D4
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D1
D2
D3
D5
D6
D7
D8
D9
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SPEX
Spectral
Fits
Thermal (Mewe)
+
Broken Power Law
Photon Spectrum
Thin Shutters In
Detector #4
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SPEX
Spectral
Fits
Thermal (Mewe)
+
Broken Power Law
Photon Spectrum
Thin Shutters In
Detector #4
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Thermal Fits to RHESSI Spectra
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SPEX
Spectral
Fits
Power Law
+
Gaussian
Photon Spectrum
Shutters Out
Detector #4
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SPEX
Spectral Fits
Broken Power Law
Thin & Thick Shutters
In
Detector #4
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SPEX
Spectral Fits
Power Law
+
3 Gaussians
Thin & Thick
Shutters In
Detector #4
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RHESSI Results
All Shutters Out
Gaussian Peak Energy from SPEX using
Power-law + N-Gaussians fit from 5 – 30 keV
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RHESSI Results
Gaussian Peak Energy from SPEX using
Power-law + N-Gaussians fit from 5 – 30 keV
A0
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A1
A3
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RHESSI Results
Equivalent Width of ~6.7-keV Peak from SPEX using
Power-law + N-Gaussians fit from 5 – 30 keV
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RHESSI Results
Power-law Index from SPEX using
Power-law + N-Gaussians Fit from 5 – 30 keV
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RHESSI Results
Gaussian Peak Energy from SPEX using
Power-law + N-Gaussians fit from 5 – 30 keV
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RHESSI Results
Power-law Flux from SPEX using
Power-law + N-Gaussians Fit from 5 – 30 keV
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Mewe & Chianti Spectra
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Energy in keV
Energy of Iron-line complex
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Equivalent Width of Iron-Line Complex
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Ionization
Equilibrium
Fe XXV
Arnaud & Rothenflug (1985)
Fe XXV
Mazzotta et al. (1998)
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Conclusions (1)
•
•
•
•
RHESSI detects the Fe-line complex at ~6.7 keV.
Peak energy is high by ~0.1 – 0.2 keV.
Peak energy varies with counting rate.
Measured equivalent width is high by
~0.5 – 1.5 keV.
• Equivalent width shows possible evidence of
nonthermal component to the continuum.
• RHESSI probably detects the Fe/Ni complex
at ~8 keV.
• Great promise for improving separation of
thermal and nonthermal components.
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Conclusions (2)
• Chianti & Mewe spectral models differ very
significantly.
• Intensity of Fe-line complex is much lower below
~15 MK in Chianti.
• Probable cause is different ionization equilibrium
models for Fe:
– Mewe uses Arnaud & Rothenflug (1985)
– Chianti uses Mazzotta et al. (1998)
• Iron abundance can be determined from RHESSI
spectra vs. time for each flare.
• GOES temperatures are suspect since they are
based on old (~1985) spectral codes
(Thomas, private communication).
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