Abstract
We describe a forward-fitting method that has been developed to reconstruct hard X-ray images of solar flares from the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI), a Fourier imager with rotation-modulated collimators that was launched on 5 February 2002. The forward-fitting method is based on geometric models that represent a spatial map by a superposition of multiple source structures, which are quantified by circular gaussians (4 parameters per source), elliptical gaussians (6 parameters), or curved ellipticals (7 parameters), designed to characterize real solar flare hard X-ray maps with a minimum number of geometric elements. We describe and demonstrate the use of the forward-fitting algorithm. We perform some 500 simulations of rotation-modulated time profiles of the 9 RHESSI detectors, based on single and multiple source structures, and perform their image reconstruction. We quantify the fidelity of the image reconstruction, as function of photon statistics, and the accuracy of retrieved source positions, widths, and fluxes. We outline applications for which the forward-fitting code is most suitable, such as measurements of the energy-dependent altitude of energy loss near the limb, or footpoint separation during flares.
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References
Aschwanden, M. J., Brown, J. C. and Kontar, E. P.: 2002, Solar Phys.,this volume.
Bevington, P. R.: 1969, Data Reduction and Error Analysis for the Physical Sciences,McGraw-Hill Book Co., New York.
Brown, J. C., Aschwanden, M. J., and Kontar, E. P.: 2002, Solar Phys.,this volume. Cash, W.: 1979, Astrophys. J. 228, 939.
Dennis, B. R. : 1996, Proc. SPIE 2804, 228.
Freeland, S. L. and Handy, B. N.: 1998, Solar. Phys. 182, 497.
Hurford, G. J.: 2002, Solar Phys.,this volume.
Kopp, R. A. and Pneuman, G. W.: 1976, Solar Phys. 50, 85.
Kosugi, T., Sawa, M., Sakao, T., Masuda, S., Inda-Koide, M., Yaji, K., and Sato, J.: 1995, The Yohkoh HXT Databook October 1991 — December 1994, Natl. Astron. Obs. Tokyo, Japan.
Lin, P. R., Dennis, B. R., Emslie, A. G., Ramaty, R., Canfield, R., and Doschek, G.: 1993, Adv. Space Res. 13, 401.
Lin, P. R., Dennis, B. R., Ramaty, R., Emslie, A. G., Canfield, R., and Doschek, G.: 1994, Geophys. Manage. 84, 283.
Lin, P. R.: 1998, Proc. SPIE 3442, 2.
Masuda, S., Kosugi, T., Hara, H., Tsuneta, S., and Ogawara, Y.: 1994, Nature 371, 495.
Press, W. H., Flannery, B. P., Teukolsky, S. A., and Vetterling, W. T:. 1986, Numerical Recipes, the Art of Scientific Computing,Cambridge University Press, Cambridge.
Sakao, T.: 1994, Ph.D. Thesis, University of Tokyo.
Sakao, T., Kosugi, T., and Masuda, S.: 1998, in T. Watanabe, T. Kosugi, and A. C. Sterling (eds.), Observational Plasma Astrophysics: Five Years of Yohkoh and Beyond, Kluwer Academic Publishers, Dordrecht, Holland; p. 273.
Sato, J., Sawa, M., Masuda, S., Sakao, T., Kosugi, T., and Sekiguchi, H.: 1998, The Yohkoh HXT Image Catalogue, October 1991 — August 1998,Nobeyama Radio Observatory/NAO, Japan. Smith D. M. et al.: 2002, Solar Phys.,this volume.
Wilks, S. S.: 1938, Ann. Math. Stat. 9, 60.
Wilks, S. S.: 1963, Mathematical Statistics, Ch. 13, Princeton University Press, Princeton.
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Aschwanden, M.J., Schmahl, E., Team, R. (2003). Reconstruction of RHESSI Solar Flare Images with a Forward Fitting Method. In: Lin, R.P., Dennis, B.R., Benz, A.O. (eds) The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). Springer, Dordrecht. https://doi.org/10.1007/978-94-017-3452-3_10
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DOI: https://doi.org/10.1007/978-94-017-3452-3_10
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