******************************************************
   PR # 22060
    We propose to observe GX339-4 simultaneously w/ASCA and BATSE onboard
    GRO. GX339-4 was observed with ASCA  in the PV phase, but the source 
    was very dim & significant X-rays were not detected. We propose three
    separate observations to study disk ionization state variations with 
    luminosity changes; since GX339-4 is very variable, we expect to ob- 
    serve three distinct luminosity levels.  GINGA satellite revealed an 
    iron K-emission line and a reflection feature from the accretion disk
    around the compact object.  With the high energy resolution of ASCA  
    SIS, we will be able to study  how the disk ionization state varies  
    with the luminosity changes.  The simultaneous BATSE data will       
    constrain the high energy end of the spectral model, yielding        
 ******************************************************