SIMBAD references

We report on the analysis of Rossi X-Ray Timing Explorer Proportional Counter Array (PCA) monitoring observations of the γ-ray binary system LS I +61° 303, covering 35 full cycles of its orbital motion. This constitutes the largest continuous X-ray-monitoring data set analyzed to date for this source. Such an extended analysis allows us to report (1) the discovery of variability in the orbital profiles of the X-ray emission, (2) the existence of a few (recent) short flares on top of the overall behavior typical of the source, which, given the PCA field of view, may or may not be associated with LS I +61° 303, and (3) the determination of the orbital periodicity using soft X-ray data alone.