XCLUMPY: X-Ray Spectral Model from Clumpy Torus and Its Application to the Circinus Galaxy

Abstract We construct an X-ray spectral model from the clumpy torus in an active galactic nucleus, designated as “XCLUMPY,” utilizing the Monte Carlo simulation for Astrophysics and Cosmology framework. The adopted geometry of the torus is the same as that in Nenkova et al. who assume a power-law distribution of clumps in the radial direction and a normal distribution in the elevation direction. We investigate the dependence of the X-ray continuum and Fe K α fluorescence line profile on the torus parameters. Our model is compared with other torus models: MYTorus model, Ikeda model, and CTorus model. As an example, we also present the results applied to the broadband X-ray spectra of the Circinus galaxy observed with XMM-Newton , Suzaku , and NuSTAR . Our model can well reproduce the data, yielding a hydrogen column density along the equatorial plane cm −2 , a torus angular width degree, and a 2–10 keV luminosity . These results are discussed in comparison with the observations in other wavelengths.