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| Paper: |
The Influence of Molecular Lines on the Measurement of Photospheric Velocities |
| Volume: |
463, 2nd ATST-EAST Workshop in Solar Physics: Magnetic Fields from the Photosphere to the Corona |
| Page: |
99 |
| Authors: |
Uitenbroek, H.; Dumont, N.; Tritschler, A. |
| Abstract: |
We use different solar atmospheric models to investigate the
influence of molecular lines on the accuracy with which
line-of-sight velocities of mass flows can be measured from Doppler
shifts. Particularly in relatively cool atmospheres molecules become
more abundant and give rise to a thick forest of perturbing lines.
Using bisectors we estimate the apparent shift introduced in the
positions of the C I 538.0 nm and Fe I 557.6 nm lines
by molecular lines in one-dimensional models with different effective
temperatures, ranging from 3750 K to 6250 K, and in a three-dimensional
section from a solar magneto-convection simulation.
We find that the core of the iron line is mostly unaffected, and
that by contrast the carbon line is severely compromised by molecular lines,
even in environments with effective temperatures similar to those
in the quiet Sun. |
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