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H. P. Jones (NASA/Goddard Space Flight Center)
An observing program using the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope and SOHO/SUMER to look for Doppler shifts and line asymmetries in coronal holes was completed in early November, 1999 in collaboration with D. Hassler. This paper presents first results from the SPM only; analysis of and comparison with the SUMER observations is in progress and will be reported at a later date. SPM spectra-spectroheliograms were obtained on 99 Nov. 3-10 (no data for Nov. 7) for two coronal holes, surrounding active regions, and the decay phase of a small flare. Images and sample spectra are displayed. The first target of opportunity for this program was a small coronal hole approaching disk center whose identification was based on EIT images but which was not identified as a hole in the NSO synoptic 1083 nm images (K. Harvey, private communication, 1999). The area did not show 1083 nm line asymmetries as are often seen in polar holes near the limb (Dupree et al, 1996). However, a larger and more prominent coronal hole was observed in the latter portion of the observing run over a wide range of heliocentric angle, including near disk center, which showed strong 1083 nm asymmetry consistent with the observations of Dupree et al (1996), Jones et al (1997), and Jones and Bender (2000). Preliminary analysis of the SUMER observations in Si II, C IV, and Ne VIII show blue shifts in the high temperature line (Hassler, private communication, 2000), and future work will involve the removal of systematics from both data sets and their careful registration and comparison with each other and with magnetograms.
This work was supported by NASA tasks 682-344-12-19-01 and 682-370-16-22-0. NSO/Kitt Peak data used here are produced cooperatively by NSF/NOAO, NASA/GSFC, and NOAA/SEL.
The author(s) of this abstract have provided an email address for comments about the abstract: hjones@noao.edu