  We present a new analytical technique, combining Reuven Ramaty High Energy
Solar Spectroscopic Imager (RHESSI) high-resolution imaging and spectroscopic
observations, to visualize solar flare emission as a function of spectral
component (e.g., isothermal temperature) rather than energy. This
computationally inexpensive technique is applicable to all spatially-invariant
spectral forms and is useful for visualizing spectroscopically-determined
individual sources and placing them in context, e.g., comparing multiple
isothermal sources with nonthermal emission locations. For example, while
extreme ultraviolet images can usually be closely identified with narrow
temperature ranges, due to the emission being primarily from spectral lines of
specific ion species, X-ray images are dominated by continuum emission and
therefore have a broad temperature response, making it difficult to identify
sources of specific temperatures regardless of the energy band of the image. We
combine RHESSI calibrated X-ray visibilities with spatially-integrated spectral
models including multiple isothermal components to effectively isolate the
individual thermal sources from the combined emission and image them
separately. We apply this technique to the 2002 July 23 X4.8 event studied in
prior works, and image for the first time the super-hot and cooler thermal
sources independently. The super-hot source is farther from the footpoints and
more elongated throughout the impulsive phase, consistent with an in situ
heating mechanism for the super-hot plasma.
