The Nuclear X-Ray Emission-line Structure in NGC 2992 Revealed by Chandra-HETGS

Abstract

We present the narrow emission-line structure revealed by a 135 ks Chandra observation of Seyfert galaxy NGC 2992, using the High Energy Transmission Grating Spectrometer. The source was observed in an historically low-flux state. Using a Bayesian Block search technique, we detected neutral Si Kα and S Kα fluorescence and two additional lines that are consistent with redshifted, ionized Si emission. The latter two features are indicative of a photoionized outflow with a velocity of ∼ 2500 {km} {{{s}}}^-1. We also observed prominent, unresolved line emission at the rest energy of Fe Kα, with a 90% confidence FWHM velocity width of < 2000 {km} {{{s}}}^-1 (< 2800 {km} {{{s}}}^-1) and equivalent width of 406-1148 eV (288-858 eV) when broad Fe Kα line emission, as detected by Suzaku, was (was not) included in the model.