Session 26 - X-ray Emission Flow, Neutron Stars & White Dwarfs.
Oral session, Monday, January 15
Salon del Rey South, Hilton

## [26.04] The X-ray Spectrum and Lightcurve of the Eclipsing LMXB 4U2129+47 in a Low State

M. Garcia (SAO), P. Callanan (HCO)

We report on the x-ray spectrum and lightcurve of the eclipsing Low-Mass X-ray Binary (LMXB) 4U2129+47 as observed with the ROSAT PSPC during its current quiescent state. Contrary to earlier indications with the ROSAT HRI, the eclipse seen during the high state is still present. The eclipse duration, amplitude, and the fraction of residual flux present during the eclipse are all consistent with on-state (ie, Einstein IPC) observations, but the statistics in the low-state data are poor. The low state luminosity of \sim 5 \times 10^33ergs/sec and spectrum with kT \sim 0.3 keV are consistent with that seen in other quiescent LMXB.

The presence of residual flux during the eclipse indicates that the x-ray source is still extended in the quiescent state, as first discovered during high state observations. If the high state model of an extended accretion disk corona is applied to the quiescent state, then the mechanism which creates the corona must be insensitive to the level of x-ray irradiation from the central source.