Mass outflow of the X-ray emission line gas in NGC 4151
S. B. Kraemer, T. J. Turner, Jullianna Denes Couto, D. M. Crenshaw, Henrique R. Schmitt, Mitchell Revalski, Travis C. Fischer
Abstract
ABSTRACT We have analysed Chandra/High Energy Transmission Gratings spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ∼ 200 pc from the nucleus. Using the first-order spectra, we measure an average line velocity ∼−230 km s−1, suggesting significant outflow of X-ray gas. We generated cloudy photoionization models to fit the first-order spectra; the fit required three distinct emission line components. To estimate the total mass of ionized gas and the mass outflow rates, we applied the model parameters to fit the zeroth-order emission line profiles of Ne ix and Ne x. We determined the total mass of ≈5.4 × 105 M⊙. Assuming the same kinematic profile as that for the [O iii] gas, derived from our analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra, the peak X-ray mass outflow rate was ≈1.8 M⊙ yr−1, at r ∼ 150 pc. The total mass and mass outflow rates are similar to those determined using [O iii], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray outflow rate does not drop off at r > 100 pc, which suggests that it may have a greater impact on the host galaxy.