Session 7: Observational Astronomy

Title: Optical and IR photometry of the Soft X-ray Transient XTE J1859+226 during the 1999 outburst cycle.
Author(s): : Zach Ioannou, C. Haswell, R.Hynes, S. Chaty, E. Harlaftis, A.Brinias, A.J. Norton, R. Fried, D. Rolfe, J.E. Solheim

We present optical and ifra-red photometry of the new X-ray transient source XTE J1859+226. The source exhibits a typical X-ray nova behaviour with a fast rise (~5 days) and an exponential decline (~23 days). Week photometric modulations are seen at several periods ranging from 9.15 hours to 20 minutes. The evolution of the spectral energy distribution of the source can be fitted very well with a model of an X-ray irradiated accretion disc.