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Serts-97 Measurements of Relative Wavelength Shifts in Coronal Emission Lines Across a Solar Active Region

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Abstract

We used slit spectra from the 18 November 1997 flight of Goddard Space Flight Center’s Solar EUV Rocket Telescope and Spectrograph (SERTS-97) to measure relative wavelength shifts of coronal emission lines as a function of position across NOAA active region 8108. The shifts are measured relative to reference wavelengths derived from spectra of the region’s nearby quiet surroundings (not necessarily at rest) because laboratory rest wavelengths for the coronal EUV lines have not been measured to sufficient accuracy for this work. An additional benefit to this approach is that any systematic uncertainties in the wavelength measurements are eliminated from the relative shifts by subtraction. We find statistically significant wavelength shifts between the spatially resolved active region slit spectra and the reference spectrum. For He II 303.78 Å the maximum measured relative red shift corresponds to a Doppler velocity ∼ +13 km s−1, and the maximum relative blue shift corresponds to a Doppler velocity ∼ −3 km s−1. For Si X 347.40 Å, Si XI 303.32 Å, Fe XIV 334.17 Å, and Fe xvi 335.40 Å the corresponding maximum relative Doppler velocities are ∼ +19 and ∼ −14, ∼ +23 and ∼ −7, ∼ +10 and ∼ −10, and ∼ +13 and ∼ −5 km s−1, respectively. The active region appears to be divided into two different flow areas; hot coronal lines are predominantly red-shifted in the northern half and either blue-shifted or nearly un-shifted in the southern half. This may be evidence that material flows up from the southern part of the region, and down into the northern part. Qualitatively similar relative wavelength shifts and flow patterns are obtained with SOHO/CDS spectra.

Keywords

Wavelength Shift Doppler Velocity Coronal Emission Line Spatial Pixel Sound Rocket Experiment 
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References

  1. Achour, H., Brekke, P., Kjeldseth-Moe, O., and Maltby, P.: 1995, Astrophys. J. 453, 945.ADSCrossRefGoogle Scholar
  2. Arnaud, M. and Raymond, J.: 1992, Astrophys. J. 398, 394.ADSCrossRefGoogle Scholar
  3. Behring, W. E., Cohen, L., and Feldman, U.: 1972, Astrophys. J. 175, 493.ADSCrossRefGoogle Scholar
  4. Behring, W. E., Cohen, L., Feldman, U., and Doschek, G. A.: 1976, Astrophys. J, 203, 521.ADSCrossRefGoogle Scholar
  5. Brekke, P.: 1993, Astrophys. J. 408, 735.ADSCrossRefGoogle Scholar
  6. Brekke, P., Hassler, D. M., and Wilhelm, K.: 1997, Solar Phys. 75, 349.ADSCrossRefGoogle Scholar
  7. Brekke, P., Kjeldseth-Moe, O., and Harrison, R. A.: 1997, Solar Phys. 175, 511.ADSCrossRefGoogle Scholar
  8. Brekke, P., Kjeldseth-Moe, O., Brynildsen, N., Maltby, P., Haugan, S. V. H., Harrison, R. A., Thompson, W. T., and Pike, C. D.: 1997, Solar Phys, 170, 163.ADSCrossRefGoogle Scholar
  9. Brosius, J. W., Davila, J. M., and Thomas, R. J.: 1998, Astrophys. Jt. Suppl. 119, 255.ADSCrossRefGoogle Scholar
  10. Brosius, J. W, Thomas, R. J., and Davila, J. M.: 1999, Astrophys. J. 526, 494.ADSCrossRefGoogle Scholar
  11. Brosius, J. W., Davila, J. M., Thomas, R. J., and Monsignori-Fossi, B. C.: 1996, Astmpkys. J. Suppl. 106, 143.ADSCrossRefGoogle Scholar
  12. Brynildsen, N., Maltby, P., Brekke, P., Haugan, S. V. H., and Kjeldseth-Moe, O.: 1999, Solar Phys. 186, 141.ADSCrossRefGoogle Scholar
  13. Chae, J., Yun, H. S., and Poland, A. I.: 1998, Astrophys. J. Suppl. 114, 151.ADSCrossRefGoogle Scholar
  14. Dere, K. P.: 1982, Solar Phys. 77, 77.ADSCrossRefGoogle Scholar
  15. Dere, K. P., Bartoe, J.-D. F., and Brueckner, G. E.: 1984, Astrophys. J. 281, 870.ADSCrossRefGoogle Scholar
  16. Doschek, G. A., Feldman, U., and Bohlin, J. D.: 1976, Astrophys. J. 205, L177.ADSCrossRefGoogle Scholar
  17. Feldman, U., Cohen, L., and Doschek, G. A.: 1982, Astrophys. J. 255, 325.ADSCrossRefGoogle Scholar
  18. Fuhr, J. R., Martin, G. A., and Wiese, W. L.: 1988, J. Phys. Chem. Ref. Data 17, Supp. No. 4.Google Scholar
  19. Hassler, D. M., Rottman, G. J., and Orrall, F. Q.: 1991, Astrophys. J. 372, 710.ADSCrossRefGoogle Scholar
  20. Kaufman, V., and Edlen, B.: 1974, J. Phys. Chem. Ref. Data 3, 825.ADSCrossRefGoogle Scholar
  21. Kelly, R. L.: 1987, J. Phys. Chem. Ref Data 16, Supp. No. 1 (Finding List).Google Scholar
  22. Kelly, R. L., and Palumbo, L. J.: 1973, NRL Report 7599, (Naval Research Laboratory, Washington, D.C.Google Scholar
  23. Monsignori-Fossi, B. C.: 1992, unpublished.Google Scholar
  24. Teriaca, L., Erdelyi, R., and Doyle, J. G.: 1999, presented at the Monterey Workshop.Google Scholar
  25. Thomas, R. J., Davila, J. M., Thompson, W.T., Kent, B. J., and Hollandt, J.: 1999, Bull. Am. Astron. Soc. 31, 850.ADSGoogle Scholar
  26. Thompson, W. T. and Brekke, P.: 1999, presented at the Monterey Workshop.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2001

Authors and Affiliations

  1. 1.Raytheon ITSS, Code 682NASA’s GSFCGreenbeltUSA
  2. 2.Laboratory for Astronomy and Solar Physics, Code 682NASA’s GSFCGreenbeltUSA
  3. 3.SM&A, Code 682NASA’s GSFCGreenbeltUSA

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