
TY  - JOUR
A1  - Greenhill, JG 
A1  - Storey, MC 
A1  - Galloway, D 
T1  - Luminosity Dependent Changes of Pulse Profiles in the X-ray Binary GX 1+4
JF  - Publications of the Astronomical Society of Australia
JO  - Publ. Astron. Soc.  Aust.
Y1  - 1998
VL  - 15
IS  - 2
SP  - 254
EP  - 258
KW  - 
UR  - https://doi.org/10.1071/AS98254 
N2  - 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. 
ER  -

