Direct Imaging
Recent observations at NSO/Sac Peak using the Dunn Solar Telescope and the High-order Adaptive Optics were done. A solid etalon at 1083nm was used to observe the He I absorption line, with significant contamination from the surrounding continuum. A movie sequence of a small solar flare was obtained on 18 Aug 2003, and short sequences of a quiescent solar filament and a limb prominence were obtained on 19 Aug 2003. Sample images are below.
Spectroscopy
Spectroscopic observations from 2002 have focussed on sunspots. The Evershed outflow has been measured using molecular absorption lines with a surprisingly fast outflow being measured, and molecular line strength variations have been compared with the continuum intensity changes across a spot. These results are described in two papers.
Penn, M.J., Cao, W.D., Walton, S.R., Chapman, G.A., Livingston, W., ``Weak Infrared Molecular Lines Reveal Rapid Outflow in Cool Magnetic Sunspot Penumbral Fibrils '' ApJ Letters, 2003, 590, L119.
Here is a figure showing the change in wavelength of a CN absorption line at different azimuthal angles within a sunspot penumbra:
Penn, M.J. Walton, S.R., Chapman, G.A., Ceja, J.A., Plick, W., ``Temperature Dependence of Molecular Line Strengths and Fe I 1565 nm Zeeman Splitting in a Sunspot '' Solar Physics, 2003, 213 p55
A map of a sunspot group in the continuum near 1565nm, and a spectrum from the center of an umbra (continuum brightness is removed) showing Zeeman splitting and molecular lines.
Finally some He I 1083nm spectra; one showing rapid red-shift velocities on the disk, and the second showing velocities in a prominence at the limb.
Spectro-polarimetry
Spectro-polarimetric observations from 2002 also focussed on sunspots. Stokes I and Stokes V maps were made of a sunspot using the Ti I 2231nm absorption line, and are discussed in the paper:
Penn, M.J., Cao, W.D., Walton, S.R., Chapman, G.A., Livingston, W., ``Imaging Spectropolarimetry of Ti I 2231nm in a Sunspot '' Solar Physics, 2003, 215, p87.
Sample spectral frames showing the 2231nm Ti I line in Stokes I and Stokes V are shown below, followed by a map of the spot:
Recent work includes full Stokes I,Q,U and V polarimetry at the g=3 Fe I 1565nm line in several sunspots. Techniques for removing instrumental polarization from data from both NSO/Kitt Peak and CSUN/SFO have been established, and fits to the corrected line profiles are currently being done. A sample spectral frame (Stokes Q) and a vector field map using a simple moments technique on the spectra are shown below:
