The Seyfert 2 galaxy Mrk 1210 was found to exhibit a flat hard X-ray component by ASCA, although ASCA could not distinguish whether it is an absorbed direct component or a reflected one. We then observed Mrk 1210 with BeppoSAX, and found that the X-ray spectral properties are quite different from those of ASCA, as have been confirmed with XMM-Newton; the flux is significantly higher than that in the ASCA observation, and a clear absorption cut-off appears below 5keV. A bright hard X-ray emission is detected up to 100keV. The reflection component is necessary to describe the BeppoSAX PDS spectrum, and represents the ASCA hard component very well. Therefore, the hard component in the ASCA spectrum is a reflected one, whose intensity is almost constant over 6 yr. This indicates that a dramatic spectral variability is attributed to a large change of the absorption column density by a factor of > 5, rather than the variability of the nuclear emission. The change in the absorption column density means that the torus is not homogeneous, but has a blobby structure with a typical blob size of < 0.001 pc.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science