Exciting Numbers to get from your TLRBSE observations

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Exciting Numbers to get from your TLRBSE
observations

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Current Topics

• The most sensitive probe of the photospheric
  magnetic field is the 1564.8nm Fe I absorption
  line.
• Evershed flows from sunspots penumbrae have been
  measured using a 1564.6nm CN absorption line.
• The CN abundance shows strange temperature
  dependence due to the chemistry of carbon
  molecules at high T.

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Slit spectra and Zeeman splitting
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1565nm is a rich spectral region
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Sidetrack Zeeman splitting is also seen in
polarized spectra
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The McMath-Pierce has oblique reflections
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Oblique reflections mix polarization components
with Mueller matrix
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Models and Empirical Methods are combined to
unmix polarization
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Magnetic Field vector components can be derived
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Vector Magnetic Maps
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Why not Stokes measurements?

• Measuring the Stokes polarized spectra is
  complicated, and correcting the telescope
  polarization contamination involves lots of
  matrix algebra.
• Interesting things can be done with just the
  intensity spectra, like measuring B vs. T.

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Magnetic Field vs. Temperature for one particular
spot
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One spot vs. another?Coldest part of many spots?
(Liv)
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How can we get T? (Blackbody)
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Particular application for TLRBSE data

• Measure B using splitting of two lines and the
  Zeeman formula
• Measure T using the ratio of the continuum
  intensity and Black-body approximation
• Does coldest part fall along Livingstons line?
• What about many points in one spot?

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Controversial Evershed Flow Measurements at 1565nm

• An absorption line formed by the CN molecule
  shows rapid Evershed outflow with Doppler shifted
  line profiles having a characteristic horizontal
  speed of 6 km s-1
• This is contrary to measurements of the Doppler
  shifts of many atomic lines.
• But, this is in agreement with Evershed flow
  models and observations of the asymmetry of
  atomic spectral lines.

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Recent models predict flow speeds up to 14 km/sec
Schlichenmaier, Jahn Schmidt, 1998, ApJ, 493,
L121
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Why use molecular lines?

• The CN molecule is broken up by collisions with
  electrons in the solar plasma at temperatures
  above 5500K, so CN is preferentially found in
  cold plasma.
• Evershed outflow seems confined to the darker
  (colder) penumbral filaments.
• A spectral line formed by CN will only probe the
  regions where the flow occurs.

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Why use molecular lines?
Dutch Open Telescope continuum movie
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Molecules probe dark fibrils (x,y)
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Molecules probe dark fibrils (z)
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3 spots, 5 days, 3 lines

• Spot NOAA 10008 observed at 1565nm 2002 June 21,
  24, 27 at r0.65 (east), 0.27 and 0.66 (west)
  from disk center.
• Spot NOAA 10008 observed at 2231nm on 2002 June
  29.
• Spots NOAA 9887 and 9888 observed on 2002 April 1
  show similar outflows and velocities at 1565nm
  other scans from CSUN/SFO from 2002 yet to be
  analyzed.

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Azimuthal binning to improve S/N
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Distribution of Doppler speeds
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Direct Mapping of CN LOS Flows

• Using some techniques to reduce noise, direct
  mapping is possible from 2002 data.

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TLRBSE Application Are these results
reproducible?

• Ideally a different camera at a different
  telescope used by a different scientist would
  measure the same velocities in the sunspot
  Evershed flow with this CN line.
• TLRBSE program provides different camera (Amber
  array) and different scientists (you).
• Proposal for Fall 2004 will use Sac Peak
  telescope, same camera, different scientist.

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Solar Chemistry of C-molecules

• The strength of the absorption line from the CN
  molecule depends critically on the number of CN
  molecules at that particular position on the
  solar surface.
• Theoretical studies of the chemistry of
  C-molecules involve CH, H2, CO, H, C2, N2, O2,
  CN, NH, NO, OH and H2O.
• Hundreds of chemical reactions, at temperatures,
  densities and pressures not easily produced in
  labs on Earth, must be considered.

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Why bother?

• The Sun provides a plasma laboratory for studying
  these reactions by measuring the relative
  abundances of these chemicals in areas with
  different temperatures.

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Most molecules become more abundant at cooler
temperatures

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CN 1564.6nm is strange
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What happens at low Temps?

• Lambert (1968) proposed that CO formation would
  dominate CN formation at lower temperatures.
• There is a CO line in this part of the spectrum!

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What happens at low Temps?
Temperature (Intensity)
CN

OH
CO
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Application to TLRBSE data

• This CN roll-over should occur at the same
  temperature in different sunspots (right?).
• A look at two spots shows different roll-over
  temperatures there are only three published
  observations.
• TLRBSE data can address this temperature point.