We present Rossi X-ray Timing Explorer , monitoring observations of the Seyfert 2 galaxy Markarian 3 spanning a 200 day period during which time the source flux varied by a factor \sim 2 in the 4–20 keV bandpass .
In broad agreement with earlier Ginga results , the average spectrum can be represented in terms of a simple spectral model consisting of a very hard power-law continuum ( \Gamma \approx 1.1 ) modified below \sim 6 keV by a high absorbing column ( N _ { H } \sim 6 \times 10 ^ { 23 } cm ^ { -2 } ) together with a high equivalent width Fe-K emission feature at 6.4 keV .
The abnormally flat spectral index is probably the signature of a strong reflection component and we consider two models incorporating such emission .
In the first the reflected signal suffers the same absorption as the intrinsic continuum , whereas in the second the reflection is treated as an unabsorbed spectral component .
In the former case , we require a very strong reflection signal ( R~ { } _ { \sim } ^ { < } ~ { } 3 ) in order to match the data ; in addition variability of both the intrinsic power-law and the reflection component is required .
The unabsorbed reflection model requires a somewhat higher line-of-sight column density to the nuclear source ( \sim 10 ^ { 24 } cm ^ { -2 } ) , but in this case the reflected signal remains constant whilst the level of the intrinsic continuum varies .
The latter description is consistent with the reflection originating from the illuminated far inner wall of a molecular torus , the nearside of which screens our direct view of the central continuum source .