  We report detailed timing and spectral analysis of RXTE-PCA data obtained
from observations during the outburst of a transient X-ray pulsar 1A 1118--61
in January 2009. The pulse profile showed significant evolution during the
outburst and also significant energy dependence - a double peaked profile upto
10 keV and a single peak at higher energy. We have also detected quasi-periodic
oscillations (QPO) at 0.07--0.09 Hz. The rms value of the QPO is 5.2% and it
shows a significant energy dependence with highest rms of 7% at 9 keV. The QPO
frequency changed from 0.09 Hz to 0.07 Hz within 10 days. The magnetic field
strength calculated using the QPO frequency and the X-ray luminosity is in
agreement with the magnetic field strength measured from the energy of the
cyclotron absorption feature detected in this source. The 3-30 keV energy
spectrum over the 2009 outburst of 1A 1118--61 can be well fitted with a
partial covering power-law model with a high energy cutoff and an iron
fluorescence line emission. The pulse phase resolved spectral analysis shows
that the partial covering and high energy cutoff model parameters have
significant changes with the pulse phase.

High Energy Astrophysical Phenomena