To gain insight into the structure and physical processes which occur in active regions and other solar features, it is essential to view those features simultaneously in emission lines which originate in widely differing temperature regimes. The SERTS waveband is well suited to this task, since it includes emission lines formed at temperatures ranging from 50, 000K to nearly 10 million K.
We observed NOAA active region 7563 (S10 W15) simultaneously with SERTS and with the Yohkoh Soft X-Ray Telescope (SXT) on 1993 August 17. SERTS obtained spatially resolved slit spectra between 280 and 420 Å, and images in the lines of He II 303.8, Mg IX 368.1, Fe XV 284.1, and Fe XVI 335.4 and 360.8. SXT obtained images through multiple broadband filters in both the full-frame imaging mode and the partial-frame imaging mode.
From the spatially resolved slit spectra, we obtained emission line intensities for lines of He II 303.8, Mg IX 368.1, Fe XIII 348.2, Si XI 303.3, Fe XIV 334.2, Fe XV 284.1, and Fe XVI 335.4 for each spatial position. These are shown in the Figures below, where frames (a) through (g) show the above EUV line intensities (and associated uncertainties as vertical lines) in ergs/ cm^2/ s/ sr; frame (h) shows the corresponding X-ray intensities (through the AlMgMn filter) in DN/ s. Based upon the spatial variations of the line intensities, active region 7563 systematically narrows when viewed with successively hotter lines, and appears narrowest in the broad band soft X-ray emission. Intensity values were excluded if their uncertainties exceeded 50%, if their line widths were narrower than instrumental, or if their Gaussian fits were deemed unacceptable (e.g., too broad).
"The Structure and Properties of Solar Active Regions and Quiet-Sun Areas Observed in Soft X-Rays with Yohkoh/SXT, and in the Extreme Ultraviolet with SERTS," J. W. Brosius, J. M. Davila, R. J. Thomas, J. L. R. Saba, H. Hara, and B. C. Monsignori-Fossi, Ap. J. 477, 969 (1997).
Last Revised: Wednesday, 29-Nov-2006 07:36:52 EST
Responsible NASA Official: joseph.davila@gsfc.nasa.gov
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