All Tables

Table 1: Best fit parameters for the EPIC-pn spectrum of Cyg X-2 in the energy band 0.4-10 keV, with a disk black body at temperature $kT_{\rm db}$ ( DISKBB in XSPEC, Mitsuda et al. 1984) and a comptonized spectrum ( COMPTT in XSPEC, Titarchuk 1994), affected by extinction of gas and dust ( TBABS in XSPEC, Wilms et al. 2000). See text for the definition of the parameters. Errors are given at 90% confidence level for one interesting parameter.
Table 2: RGS fitting results for the oxygen region in Cyg X-2. The parameters for the continuum emission are taken from the broad-band spectrum. The energies are measured in keV and the Equivalent Width ( EW) in eV. Model 1 fits the O vicinity with 3 edges (two of which are from atomic O) and 2 absorption lines (one from atomic neutral O and the other from molecular O). Model 2 interprets the spectrum in terms of absorption by atomic O, either neutral or mildly ionized. Errors are given at 90% confidence for one interesting parameter.
Table 3: Relevant absorption edges in the RGS spectrum of Cyg X-2. The energy, the corresponding wavelength, and the optical depth ( $\tau$ ) were obtained from the data. The equivalent total hydrogen column density $N_{\rm H}$ was derived from the ISM abundances of Wilms et al. (2000). These are to be compared with the best-fit $\mbox{$N_{\rm H}$ } =(2.20\pm 0.02)\times 10^{21}\ {\rm cm}^{-2}$ , measured by RGS. Errors are given at 90% confidence level.