
TY  - JOUR
A1  - Storey, Michelle C 
A1  - Kotani, T 
A1  - Greenhill, JG 
T1  - Investigating Pulse Morphology in GX 1+4
JF  - Publications of the Astronomical Society of Australia
JO  - Publ. Astron. Soc.  Aust.
Y1  - 1998
VL  - 15
IS  - 2
SP  - 217
EP  - 221
KW  - 
UR  - https://doi.org/10.1071/AS98217 
N2  - Observational and theoretical evidence points to the existence of an unusually high magnetic field on GX 1+4. The pulsar is thus an ideal laboratory for studying two-photon cyclotron emission, an important source of photons of frequency significantly less than the cyclotron frequency in X-ray pulsars. Low-frequency approximations to the two-photon cyclotron emission transition probabilities are derived. These are used to calculate the theoretical opening angle of the double-humped pulse shape predicted by the two-photon cyclotron emission model. The theoretical pulse shape, incorporating the effects of gravitational light bending, is compared with observations of GX 1+4. Observed light curves have opening angles consistent with the theoretically predicted maximum value. 
ER  -

