Coordinated EXOSAT and Optical Observations of the X-Ray Burster 4U1737-44
Charles, P. A.; Corbet, R. H. D.; Smale, A. P.; Menzies, J. W.; Mack, P.
United Kingdom, South Africa
Abstract
We present the first results of an EXOSAT observation of the low-mass X-ray burster 4U1735-44. The ME data show low-amplitude variations in the persistent flux including two 5% dips separated by ∼4 hours. The structure of the single observed burst is briefly described. Five hours of simultaneous B-band photometry were obtained at SAAO with 12 minute time resolution; a strong anti-correlation is shown to exist between the X-ray and optical flux, with a high level of significance. A model for this behaviour is suggested, based on reprocessing of the X-ray flux in a corona or stellar wind.