Title of article :
The Discovery of H2O Maser Emission in Seven Active Galactic Nuclei and at High Velocities in the Circinus Galaxy
Author/Authors :
Greenhill، L. J. نويسنده , , Kondratko، P. T. نويسنده , , Lovell، J. E. J. نويسنده , , Kuiper، T. B. H. نويسنده , , Moran، J. M. نويسنده , , Jauncey، D. L. نويسنده , , Baines، G. P. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی 1 سال 2003
Abstract :
Competing models for broad spectral features in the soft X-ray spectrum of the Seyfert I galaxy Mrk 766 are tested against data from a 130 ks XMM-Newton observation. A model including relativistically broadened Ly(alpha) emission lines of O VIII, N VII, and C VI is a better fit to 0.3-2 keV XMM RGS data than a dusty warm absorber. Moreover, the measured depth of neutral iron absorption lines in the spectrum is inconsistent with the magnitude of the iron edge required to produce the continuum break at 17-18 ? in the dusty warm absorber model. The relativistic emission line model can reproduce the broadband (0.1-12 keV) XMM EPIC data with the addition of a fourth line to represent emission from ionized iron at 6.7 keV and an excess due to reflection at energies above the iron line. The profile of the 6.7 keV iron line is consistent with that measured for the low-energy lines. There is evidence in the RGS data, at the 3 (sigma) level, of spectral features that vary with source flux. The covering fraction of warm absorber gas is estimated to be 12%. Iron in the warm absorber is found to be overabundant with respect to CNO, compared to solar values.
Keywords :
NGC 2979 , NGC 5643 , Seyfert , IRAS F19370-0131 , NGC 6926 , molecules , ISM , masers , NGC 2824 , galaxies , Individual , Circinus , ESO 269-G012 , NGC 6300 , active
Journal title :
Astrophysical Journal
Journal title :
Astrophysical Journal