New Chandra Observations of NGC 4151: Modelling the X-Ray Absorption

We present the results of the a new spectral analysis of the Seyfert 1.5 galaxy NGC 4151, using data obtained from the simultaneous UV/ X-Ray observations with Hubble STIS Echelle and Chandra HETG in 2014. Past observations of NGC 4151 show high variability in the continuum flux, and our data found the galaxy in a very low flux state, in both X-Ray and UV. We propose an X-Ray model consistent of an intrinsic broken powerlaw continuum, attenuated by absorber components with a range of ionization and column densities. Preliminary analysis of the UV data rules out the possibility of a larger column density, as proposed by Kraemer et. al (2005) for a similar low flux state dataset from 2000. Instead, we suggest the presence of an additional, highly ionized absorber. In our model, the three main components of absorption span a range of radial distances, with the nearer ones filtering the ionizing radiation incident on the further ones. The changes in absorption appear to be principally due to the changes in ionization state/opacity of the individual components.