Advances in Astronomy and Space Physics, Volume 3, Issue 2 (2013)

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

A. A. Vasylenko1, E. Fedorova2, V. I. Zhdanov2

1Faculty of Physics, Taras Shevchenko National University of Kyiv, Glushkova ave. 4, 03127 Kyiv, Ukraine
2Astronomical Observatory, Taras Shevchenko National University of Kyiv, Observatorna str. 3, 04053 Kyiv, Ukraine

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 66.98−1.34+2.63 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.

Keywords:
galaxies: Seyfert: individual: NGC3281 - galaxies: nuclei - X-rays: galaxies