The Properties of the Absorbing and Line Emitting Material in IGR J16318-4848

Abstract

We analyzed the 2003 Target of Opportunity XMM-Newton observation of IGR J16318-4848, to derive the properties of the matter responsible for the obscuration and for the emission of Fe and Ni lines. The line of sight material has a column density of about 2×10²⁴ cm^-2 but, from the Fe Kα line EW and Compton Shoulder, we argue that the average column density is a few ×10²³ cm^-2, while the covering factor is about 0.1-0.2. The iron Kα line varies on time scales as short as 1000 s, implying a size of the emitting region less than 3×10¹³ cm. An ongoing XMM-Newton/INTEGRAL monitoring campaign is confirming the non-transient nature of the source.