The Reuven Ramaty High Energy Solar Spectroscopic Imager {RHESSI}
telescope produces hard X-ray images by Fourier imaging techniques
that are capable of determining the sizes and shapes of
sources with spatial scales in the range ~2''-180''. Applying
the method of Unpixelized Forward Fitting to {RHESSI} modulation
profiles from simple flares, we have identified the presence of `halo'
sources whose size scale (~40'' greatly exceeds the `core''
sizes (<= 6''-14''). Although such `core-halo' structures have been
observed at radio wavelengths using a similar technique, the radio and
hard X-ray phenomena may be different. These observations raise
questions about the nature of these `halos'. Among the
possibilities are that they are albedo sources, thin-target loops, or
unidentified diffuse structures.
Authors: Schmahl, E.J., and Hurford, G. J.
Projects:
Publication Status: Solar Physics (2002, Special Issue on RHESSI)
Last Modified: 2002-10-04 12:42