* Max-Planck Institut für Extraterrestrische Physik, Giessenbachstr., 8046 Garching, Germany
** Physics Department, University of Crete, P.O. Box 470, Heraklion, Crete, Greece
Abstract:
ROSAT performed the first, spectrally resolved, soft X-ray observations of Her X-1 in the SHORT-ON state of the 35d cycle. The data were taken during the All-Sky survey covering the range 0.1–2.4 keV. The mean luminosity in the ROSAT bandpass is 1.5 × 1036ergs sec−1. Timing analysis of the data revealed a highly significant signal at a period of 1.237749(1) sec. Finally, we present evidence to support the hypothesis that the resuction in intensity during the SHORT-ON state is caused by hot matter absorption in the disk.