Searching for Sigmoids in SOHO/CDS

Sigmoidal structures observed in X-rays have been shown to be precursors to CMEs, existing in some cases for several days before an eruption (Sterling and Hudson 1997,ApJ,491,L55; Canfield et al, 1999, GRL, 26, 6, 627). While these S-shaped structures are most apparent in X-ray active region observations, they may be manifestations of a more general helical magnetic structure having observational signatures at other wavelengths. We will present preliminary results of a survey search for sigmoidal structures and other CME tracers in archived SOHO/CDS data for a series of active regions known to contain erupting sigmoidal structures in X-ray observations. We are particularly interested in determining the relative locations and temperatures of these tracers, and will see to what extent the data answers questions such as, if S shapes are observed at different wavelengths do they line up, or is there a spatial displacement and/or rotation of angle of S that corresponds with height/temperature variation ? How does the appearance of the region vary over the lifetime of the observed x-ray sigmoidal structure ? After an eruption, how much if any of the S shape remains, and at what spatial and spectral locations ? We will use the results of this comparison survey to consider what the implications are for the underlying magnetic field structure, and the location and variation of heating throughout it.