The Origin of Emission and Absorption Features in Ton S180ChandraObservations

We present new interpretation of Ton S180 spectrum obtained by {\it Chandra}Spectrometer (Low Energy Transmission Grating). Several narrow absorption linesand a few emission disk lines have been successfully fitted to the data. Wehave not found any significant edges accompanying line emission. We propose theinterpretation of narrow lines consistent with the paper recently written byKrolik (2002), where warm absorber is strongly inhomogeneous. Such situation ispossible in so called multi-phase medium, where regions with differentionization states, densities and temperatures may coexist in thermalequilibrium under constant pressure. We illustrate this scenario withtheoretical spectra of radiation transfered through a stratified cloud withconstant pressure (instead of constant density) computed by code {\sc titan} inplane parallel approximation. Detected spectral features are faint and theirpresence do not alter the broad band continuum. We model the broad bandcontinuum of Ton S180 assuming an irradiated accretion disk with a dissipativewarm skin. The set of parameters appropriate for the data cannot be determineduniquely but models with low values of the black hole mass have too hot andradially extended warm skin to explain the formation of soft X-ray disk linesseen in the data.Comment: accepted to Ap