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Astron. Astrophys. Suppl. Ser. 140, 373-382

Instantaneous positions of microwave solar bursts: Properties and validity of the multiple beam observations

C.G. Giménez de Castro1 - J.-P. Raulin1 - V.S. Makhmutov2 - P. Kaufmann1 - J.E.R. Costa1

Send offprint request: C.G. Giménez de Castro

1 - CRAAE: (Mackenzie, INPE, USP, UNICAMP), Instituto Presbiteriano Mackenzie, Rua de Consolação 896, 01302-000, S. Paulo, SP, Brazil
2 - P.N. Lebedev Institute RAS, Leninsky Prospect 53, 117924 Moscow, Russia

Received May 28; accepted June 9, 1999


The multiple beam technique determine burst sources positions when their angular extent are small compared with the beam shapes. We show for the first time that we can check the above condition with the simultaneous observation using at least four beams. The developed technique is not critically dependent on source shapes. By means of simulations we found that for narrow 1 arcmin long sources the uncertainties in position determination are less than 5 arcsec, and much better for symmetrical sources. The influence of side lobes on source positions determinations was found to be negligible. A qualitative method was developed when data from only three beams are available. Both methods are applied to the analysis of a solar burst observed with multiple beams at 48 GHz with the Itapetinga 13.7 m antenna. The multiple beam technique also offers the unique advantage to determine flux density irrespectively from the position displacements of the source with respect to the beams, or vice versa.

Key words: sun: flares -- sun: radio radiation -- techniques: interferometric

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