Solar High Resolution Spectral Observations Compared with Numerical Simulations

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Solar High Resolution Spectral Observations
Compared with Numerical Simulations
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Wavelength 7200 Å
Diffraction limit 0.24 160 km
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High resolution spectral observations

• Need to resolve sub-arcsec structures
• Need high temporal resolution (seconds at most)
• Need high spectral resolution - R gt 200,000

Very low photon flux

• Spectrographs inherently inefficient

Imaging spectroscopy
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Imaging Spectroscopy(rapidly tunable narrowband
filters)

• High transparency (15-20)
• Large 2-D field of view
• Narrow passbands (R gt 200,000)

Sequential spectral sampling within lines Limited
number of available lines
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Interferometric Bidimensional Spectrometer (IBIS)

• FeI 709.0 nm , gL 0
• 16 spectral positions
• Scan rate 4 s

• 512x512 pix, 0.16/pix
• Quiet area

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Simulations and Spectral Synthesis
3-D radiative HD simulation (provided by M.
Asplund) 6x6 Mm area, 120 km step (original
res30 km) 1 Mm height, from 800 to -200 km.
Step _at_10 km Six snapshots LTE synthesis of FeI
709.04 nm

• Synthetic data smeared with telescope and
  atmospheric PSF,
• plus instrumental spectral transmission

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Monochromatic Images
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Monochromatic Intensities
blue wing
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Monochromatic Intensities
red wing
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Monochromatic Images
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Monochromatic Intensities -data
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Monochromatic Intensities - data vs simulations
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Intensity distribution with wavelength
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Velocity Distribution
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Velocity Distribution
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Equivalent width - data vs simulations
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Reverse Granulation
continuum
continuum
line core
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Reverse Granulation tl 1 distribution
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Average Profiles
Fe7.67
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Conclusions
Very good agreement of high res observations
with HD simulations LTE spectral synthesis
Fe I 709.04 nm is a perfect line for the test
Validates both the realism of the simulations
AND the reliability of the instrument
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Monochromatic Intensities -data
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Simulations Single Profiles
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Comparison with Simulations Average Profiles
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Bright Point Profiles
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Contrast (?)
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Intensity distribution Granules and Intergranules
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Monochromatic spatial power spectra
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