Observations of Sy2 galaxy NGC 3281 by XMM-Newton and INTEGRAL satellites

Abstract

We present the results of the analysis of X-ray properties of the Seyfert 2 galaxy NGC 3281, based on the observational data obtained by XMM-Newton and INTEGRAL within the energy ranges 0.2-12 keV and 20-150 keV, respectively. The XMM-Newton spectrum of this object is presented for the first time. We show that fitting the X-ray spectrum of this galaxy with models based on the reflection from the disc with infinite column density yields non-physical results. A more appropriate fit takes into account both transmitted and reflected emission, passed through a gas-dust torus-like structure. Keeping this in mind, to model the inhomogeneous clumpy torus, we used the MYTorus model. Hence, we conclude that the torus of NGC 3281 is not a continuous structure, but rather consists of separate clouds, which is in a good agreement with the results of near-IR observations. Using this assumption, we found that the torus inclination angle and the hydrogen column density are 66.98⁺²˙⁶³ ₋₁.₃₄ degrees and 2.08⁺⁰˙³⁵₋₀.₁₈ × 10²⁴ cm⁻², respectively. Also, emissions of hot diffuse gases with temperature ∼ 590 eV, and warm absorption, were detected.