SIMBAD references

We have made BeppoSAX observations of the Seyfert 2/1.9 galaxy ESO 103-G35, which contains a nuclear maser source and is known to be heavily absorbed in the X-rays. Analysis of the X-ray spectra observed by BeppoSAX in 1996 October and 1997 October yields a spectral index α_E=0.74±0.07 (F_ν∝ν^–αE_^), which is typical of Seyfert galaxies and consistent with earlier observations of this source. The strong, soft X-ray absorption has a column density N_H of 1.79±0.09x10²³ cm^–2, again consistent with earlier results. The best-fitting spectrum is that of a power law with a high-energy cutoff at 29±10 keV, a cold (E=6.3±0.1 keV, rest frame), marginally resolved (σ=0.35±0.14 keV, FWHM ∼31±12x10³ km.s^–1) Fe Kα line with EW 290⁺¹⁰⁰_–80 eV (1996), and a mildly ionized Fe K edge at 7.37^+0.15_–0.21 keV, τ=0.24^+0.06_–0.09. The Kα line and cold absorption are consistent with origin in an accretion disk/torus through which our line of sight passes at a radial distance of ∼50 pc. The Fe K edge is mildly ionized, suggesting the presence of ionized gas, probably in the inner accretion disk close to the central source or in a separate warm absorber. The data quality is too low to distinguish between these possibilities, but the edge-on geometry implied by the water maser emission favors the former. Comparison with earlier observations of ESO 103-G35 shows little or no change in spectral parameters while the flux changes by factors of a few on timescales of a few months. The 2-10 keV flux decreased by a factor of ∼2.7 between 1996 October and 1997 October with no detectable change in the count rate greater than 20 keV (i.e., the Phoswich Detector System data). Spectral fits to the combined data sets indicate either a significant hardening of the spectrum (α_E∼0.5) or an approximately constant or delayed response reflection component. The high-energy cutoff (29±10 keV) is lower than the typical ∼300 keV values seen in Seyfert galaxies. A significant subset of similar sources would affect current models of the active galactic nucleus contribution to the cosmic X-ray background which generally assume a high-energy cutoff of ∼300 keV.