We report here discovery of Quasi Periodic Oscillations ( QPOs ) in the High Mass X-ray Binary ( HMXB ) Pulsar XTE J0111.20–7317 during a transient outburst in this source in December 1998 .
Using observations made with the proportional counter array of the Rossi X-ray Timing Explorer during the second peak and the declining phase of this outburst we have discovered a QPO feature at a frequency of 1.27 Hz .
We have ruled out the possibility that the observed QPOs can instead be from the neighbouring bright X-ray pulsar SMC X-1 .
This is the highest frequency QPO feature ever detected in any HMXB pulsar .
In the absence of a cyclotron absorption feature in the X-ray spectrum , the QPO feature , along with the pulse period and X-ray flux measurement measurement helps us to constrain the magnetic field strength of the neutron star .