A Cessation of X-ray Dipping Activity in X1254-690
read the original abstract
We present results from a campaign of simultaneous X-ray and optical observations of X1254-690 conducted using the Rossi X-ray Timing Explorer and the CTIO 1.5m telescope. We find that the usually-observed deep X-ray dipping is not seen during the times of our observations, with an upper limit of ~2% on any X-ray orbital variation, and that the mean optical variability has declined in amplitude from 0.40+-0.02 mag (in V) to 0.28+-0.01 mag. These findings indicate that the vertical structure on the disk edge associated with the impact point of the accretion stream has decreased in angular size from 17-25 degrees to <10 degrees, and support the suggestions of previous modeling work that the bulge provides 35-40% of the contribution to the overall optical modulation. The average optical and X-ray brightnesses are comparable to their values during dipping episodes, indicating that the mean accretion rate and disk radius remain unchanged.
This paper has not been read by Pith yet.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.