X-RAY IMAGING OF THE SEYFERT 2 GALAXY CIRCINUS WITH Chandra

We present results from the zeroth-order imaging of a Chandra HETGS observation of the nearby Seyfert 2 galaxy Circinus. Twelve X-ray sources were detected in the ACIS-S image of the galaxy, embedded in diffuse X-ray emission. The latter shows a prominent (∼ 18) soft “plume” in the N-W direction, coincident with the [O III] ionization cone. The radial profiles of the brightest X-ray source at various energies are consistent with an unresolved (FWHM ∼ 0.8) component, which we identify as the active nucleus, plus two extended components with FWHMs ∼ 2.3 and 18, respectively. In a radius of 3, the nucleus contributes roughly the same flux as the extended components at the softest energies ( < ∼ 2 keV). However, at harder energies (> 2 keV), the contribution of the nucleus is dominant. The zeroth-order ACIS spectrum of the nucleus exhibits emission lines at both soft and hard X-rays, including a prominent Fe Kα line at 6.4 keV, showing that most of the X-ray lines previously detected with ASCA originate in a compact region ( < ∼ 15 pc). Based on its X-ray spectrum, we argue that the 2.3 ′′ extended component is scattered nuclear radiation from nearby ionized gas. The large-scale extended component includes the emission from the N-W plume and possibly from the outer starburst ring. Subject headings: galaxies: active — galaxies: nuclei — galaxies: Seyfert — galaxies: individual (Circinus) — X-rays: galaxies