An ASCA X-ray observation of 1E 1724-3045 in the globular cluster Terzan 2

The bright persistent X-ray source and type I X-ray burster 1E 1724-3045 lo cated in the globular cluster Terzan 2 was observed by ASCA for about 10 ks ec on September 24-25th, 1995 while it was in its hard state, with a lumino sity of similar to 6 x 10(36) ergs s(-1) in the 0.5-10 keV band (d=7.7 kpc) . The ASCA spectrum is hard, and reveals the presence of a soft component b elow 2-3 keV. When combined with non simultaneous RXTE/HEXTE data, we show that the ASCA spectrum can be adequately fitted by a Comptonization model f or which the electron temperature is similar to 30 keV, the optical depth i s similar to 3 for a spherical scattering cloud. The soft component carries off about 13%, and 35% of the 0.1-200 keV luminosity for a blackbody and d isk blackbody fit respectively. It is more likely to arise from the accreti on disk, whereas the hard Comptonized component is generated in a hot bound ary layer interior to the disk. The column density measured towards the sou rce (N-H similar to 1.0 x 10(22) cm(-2)) is consistent with the value expec ted from the optical reddening of the cluster. No emission lines were detec ted, and an upper limit of 30 eV for the equivalent width of a 6.4 keV line (sigma = 0.1 keV) has been derived.