New observations of the vela X-1 cyclotron lines with RXTE - Preliminary results

We present preliminary results from a new, extended RXTE observation of Vel a X-l. The main goal of this observation was to settle the question of the existence and energy of the cyclotron line features in the high energy X-ra y spectrum. Previous observations with RXTE and BeppoSAX have differed in t heir conclusions, emphasising the uncertainties caused by the imperfect con tinuum description. While our results are still preliminary, they do indicate cyclotron lines a t both similar to 22 keV and similar to 51keV, confirming earlier results.