
%0 Journal Article
%A Greenhill, JG 
%A Storey, MC 
%A Galloway, D 
%T Luminosity Dependent Changes of Pulse Profiles in the X-ray Binary GX 1+4
%J Publications of the Astronomical Society of Australia
%D 1998/07/01
%V 15
%N 2
%P 254-258
%K 
%R https://doi.org/10.1071/AS98254
%U https://www.publish.csiro.au/paper/AS98254 
%X We have reviewed the X-ray pulse profiles from a large number of observations of the accreting binary pulsar GX 1+4 obtained during the last 25 years. The profiles cover various energy ranges between 1 and 100 keV. Using these data we present a coherent picture of present and past pulse profiles and the variations of these pulse profiles with time. The pulse shape is dependent on both the X-ray luminosity and whether the pulsar is spinning up or down. Profiles measured during the GX 1+4 high state in the 1970s are all trailing edge bright. Subsequently the profiles have generally been symmetric or leading edge bright. Rossi X-ray Timing Explorer (RXTE) satellite data taken in July 1996 show that similar pulse shape variations can occur on a timescale of hours. The implications of this new information for accretion models is discussed. 
