The X-ray source in the core of 47 Tucanae

The authors present new data on the X-ray source lying in the core of 47 Tuc that is the brightest of the dim globular cluster X-ray sources. From the recalibrated IPC Einstein satellite data the X-ray spectrum was obtained [thermal bremsstrahlung with kT = 2 (+4, -1) keV and no intrinsic absorption]. X-ray variability is present at time scales of days, hours and tens of minutes. In addition the authors have discovered transient periodic pulsations at period 120.200 s. Rapid periodic pulsations at period 4.580 s are also marginally present. The authors 'apresent the results of a CCD and image tube optical search for a faint blue variable object in the X-ray source field. The limiting magnitude U = 17 [M_U ≡ 3.6] is reached. A possibly UV and variable object stands out in the U CCD frames. The nature of the X-ray source - cataclysmic variable or transient low mass X-ray binary is discussed.