SIMBAD references

The luminous X-ray binary and black hole candidate LMC X-1 has been observed with the Rossi X-Ray Timing Explorer to search for quasi-periodic oscillations (QPOs) previously reported in its high state. The source was observed monthly in a series of nine observations. Analysis of the temporal variations shows no evidence for QPOs or other periodic changes, but correlations between the high-energy light curve and hardness of the spectrum are described. Spectral fits with two-component models demonstrate that the hardness variations come from changes in the intensity of the high-energy power-law tail.