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Session 44 - Stellar X-Ray Sources.
Display session, Tuesday, January 14
Metropolitan Ballroom,
We present the results of observations of the pulsating X-ray source 1E1048.1-5937 made with the ASCA GIS detectors. The source continues to exhibit spin-down at the faster rate reported from ROSAT observations rather the slower spin-down rate initially measured. The X-ray spectrum can be satisfactorily fit with a power law model and we cannot discriminate between this and the power law plus blackbody combination used for two other members of this class. The mean flux is approximately a factor of three weaker than measured with EXOSAT which is consistent with X-ray emission being powered by accretion. In addition, we obtained optical spectra of a number of stars within the EXOSAT error box with the Anglo-Australian Telescope and failed to identify a counterpart. While these results reinforce the similarity with 1E2259+586, the pulsed fraction of 1E1048.1-5937 is much larger with little energy dependence. Several members of this class will also be observed with XTE and preliminary results will be presented from those targets that have been observed.
The author(s) of this abstract have provided an email address for comments about the abstract: corbet@lheamail.gsfc.nasa.gov