The broad-band X-ray spectrum of Mrk 3 |
| |
| Authors: | R G Griffiths R S Warwick I Georgantopoulos C Done & D A Smith |
| |
| Institution: | Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH,;Astronomical Institute, National Observatory of Athens, Lofos Koufou, Palaia Penteli, Athens, GR-15236, Greece,;Department of Physics, University of Durham, South Raod, Durham DH1 3LE |
| |
| Abstract: | We use non-simultaneous Ginga ASCA ROSAT observations to investigate the complex X-ray spectrum of the Seyfert 2 galaxy Mrk 3. We find that the composite spectrum can be well described in terms of a heavily cut-off hard X-ray continuum, iron Kα emission and a soft X-ray excess, with spectral variability confined to changes in the continuum normalization and the flux in the iron line. Previous studies have suggested that the power-law continuum in Mrk 3 is unusually hard. We obtain a canonical value for the energy index of the continuum (i.e., α ≈ 0.7) when a warm absorber (responsible for an absorption edge observed near 8 keV) is included in the spectral model. Alternatively, the inclusion of a reflection component yields a comparable power-law index. The soft-excess flux cannot be modelled solely in terms of pure electron scattering of the underlying power-law continuum. However, a better fit to the spectral data is obtained if we include the effects of both emission and absorption in a partially photoionized scattering medium. In particular, the spectral feature prominent at ～ 0.9 keV could represent O VIII recombination radiation produced in a hot photoionized medium. We discuss our results in the context of other recent studies of the soft X-ray spectra of Seyfert 2 galaxies. |
| |
| Keywords: | galaxies: active galaxies: individual: Mrk 3 galaxies: Seyfert X-rays: galaxies |
|
|
