Abstract
For the leading part of sunspot group NOAA 8323, which rapidly changed its complex structure, a time series of the line-of-sight (LOS) component of the velocity field was obtained. With a two-dimensional Fabry–Pérot spectrometer, the magnetically insensitive line Fe i 557.6 nm was scanned. The inclination of the LOS (heliographic angle) to the vertical was θ=28.5°. The umbra of the observed spot was divided by a system of light bridges into several parts. The spatial and temporal velocity field also exhibits a considerable complexity: in one extended umbral area there is a downward flow of 1 km s−1 relative to other dark sub-umbrae. At the center-side penumbra, with a line-of-sight Evershed outflow of 1.5 km s−1, a persistent patch, somewhat darker than the average penumbra, has a LOS velocity of 1.3 km s−1 in opposite direction, probably a downflow. At the limb-side penumbra, a photosphere-like area is interspersed, interrupting the Evershed flow which resumes with typical strength beyond this feature towards the outer penumbral boundary. Most interesting is the behavior of the light bridges, which have a slight blue shift, interrupted by short events of strong blue or red shifts which – within the time resolution of 35 s – instantly affect a considerable part of a light bridge.
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Asai, A., Ishii, T. T., and Kurokawa, H.: 2001, Astrophys. J. 555, L65.
Balthasar, H.: 1985, Solar Phys. 99, 31.
Balthasar, H.:1988, Astron. Astrophys. Suppl. 72, 473.
Balthasar, H., Schleicher, H., Bendlin, C., and Volkmer, R.: 1996, Astron. Astrophys. 315, 603.
Balthasar, H., Martínez Pillet, V., Schleicher, H., and Wöhl, H.: 1998, Solar Phys. 182, 65.
Beckers, J. M. and Schröter, E. H.: 1969, Solar Phys. 10, 384.
Bogdan, T. J.: 2000, Solar Phys. 192, 373.
Bruls, J. H. M. J., Lites, B. W., and Murphy, G. A.: 1991, in L. J. November, (ed.), Solar Polarimetry, Proceedings of the Eleventh National Solar Observatory/Sacramento Peak Summer Workshop, Sunspot, New Mexico, 27-31 August 1990, p. 444.
Gangadhara, J. A. and Hasan, S. S.: 1997, Astron.Astrophys. 327, 786.
Hirzberger, J., Bonet, J.A., Sobotka, M., Vázquez, M., and Hanslmeier, A.: 2002, Astron. Astrophys. 383, 275.
Holweger, H. and Müller, E. A.: 1974, Solar Phys. 39, 19.
Kentischer, T. J., Schmidt, W., Sigwarth, M., and v. Uexküll, M.: 1998, Astron. Astrophys. 340, 569.
Kollatschny, W., Stellmacher, G., Wiehr, E., and Falipou, M. A.: 1980, Astron. Astrophys. 86, 245.
Kuera, A., Balthasar, H., Rybák, J., and Wöhl, H.: 1998, Astron. Astrophys. 332, 1069.
Leka, K. D.: 1997, Astrophys. J. 484, 900.
Lites, B. W., Bida, T. A., Johannesson, A., and Scharmer, G. B.: 1991, Astrophys. J. 373, 683.
McIntosh, S. P.: 1981, in L. E. Cram and J. H. Thompson (eds.), Physics of Sunspots, Sunspot, SPO, p. 7.
Muller, R.: 1979, Solar Phys. 61, 297.
Rimmele, T. R.: 1994, Astron. Astrophys. 290, 972.
Rimmele, T. R.: 1997, Astrophys. J. 490, 458.
Rüedi, I., Solanki, S. K., and Livingston, W.: 1995, Astron. Astrophys. 302, 543.
Sankarasubramanian, K. and Rimmele, T.: 2002, Astrophys. J. 576, 1048.
Schleicher, H., Balthasar, H., Kentischer, T. J., and Wöhl, H.: 2000, in C. Fang, J.-C. Hénoux, and M. D. Ding (eds.), Understanding Solar Active Phenomena, Proceedings of the 1st Franco-Chinese Meeting on Solar Physics, 2-5 November 1999, Xi'an, China, published by International Academic Publishers & World Publishing Corporation, Beijing, China, p. 117.
Schlichenmaier R. and Schmidt W.: 2000, Astron. Astrophys. 358, 1122.
Schmidt, W. and Balthasar, H.: 1994, Astron. Astrophys. 283, 241.
Sheeley, N. R.: 1972, Solar Phys. 25, 98.
Shine, R. A., Title, A. M., Tarbell, T. D., Smith, K., Frank, Z. A., and Scharmer, G.: 1994, Astrophys. J. 430, 413.
Sobotka, M.: 1997, in B. Schmieder, J.C. del Toro Iniesta, and M. Vázquez (eds.), First Advances in Solar Physics Euroconferences: Advances in Physics of Sunspots, ASP Conf. Ser. 118, p. 155.
Sobotka, M., Bonet, J. A., and Vázquez, M.: 1993, Astrophys. J. 415, 832.
Sobotka, M., Bonet, J. A., and Vázquez, M.: 1994, Astrophys. J. 426, 404.
Stix, M.: 2002, The Sun, 2nd edition, Springer-Verlag, Berlin, p. 361.
Title, A. M., Frank, Z. A., Shine, R. A., Tarbell, T. D., Topka, K. P., Scharmer, G., and Schmidt, W.: 1993, Astrophys.J. 403, 780.
Zirin, H. and Wang, H.: 1990, Solar Phys. 125, 45.
Zwaan, C.: 1992, in J. H. Thomas and N. O. Weiss (eds.), Sunspots: Theory and Observations, Proceedings of the NATO Advanced Research Workshop on the Theory of Sunspots, Cambridge, UK, 22-27 September, 1991, p. 75.
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Schleicher, H., Balthasar, H. & Wöhl, H. Velocity Field of a Complex Sunspot with Light Bridges. Solar Physics 215, 261–280 (2003). https://doi.org/10.1023/A:1025688927043
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DOI: https://doi.org/10.1023/A:1025688927043