Photoionized emission and absorption features in the high-resolution X-ray spectra of NGC 3783

Abstract

Our Swift monitoring program triggered two joint XMM-Newton, NuSTAR and HST observations on 11 and 21 December 2016 targeting NGC 3783, as its soft X-ray continuum was heavily obscured. Consequently, emission features, including the O vii radiative recombination continuum, stand out above the diminished continuum. We focus on the photoionized emission features in the December 2016 RGS spectra, and compare them to the time-averaged RGS spectrum obtained in 2000-2001 when the continuum was unobscured. A two-phase photoionized plasma is required to account for the narrow emission features. These narrow emission features are weakly varying between 2000-2001 and December 2016. We also find a statistically significant broad emission component in the time-averaged RGS spectrum in 2000-2001. This broad emission component is significantly weaker in December 2016, suggesting that the obscurer is farther away than the X-ray broad-line region. In addition, by analyzing the archival high-resolution X-ray spectra, we find that nine photoionized absorption components with different ionization parameters and kinematics are required for the warm absorber in X-rays.

The nuclear environment of the NLS1 Mrk 335: Obscuration of the X-ray line emission by a variable outflow

“…These spectra are similar to those found in NGC 5548 and NGC 3783 (Kaastra et al 2014;Mao et al 2018Mao et al , 2019, where major obscuration events caused by outflowing absorption cause large flux drops at low energies and reveal the soft X-ray emission lines. In this case, however, the flux drop is intrinsic to the source, and we see the effect of the outflow acting on the emission lines.…”

Multi-wavelength campaign on NGC 7469

“…After fitting the two narrow emission components, we detected an excess fit residual in the O vii triplet at 22 Å, which required an additional component. A broad emission component was found to significantly improve the fit to the spectra of NGC 5548 (Mao et al 2018) and NGC 3783 (Mao et al 2019), therefore, a third PION emission component (EM3), coupled with a Gaussian velocity broadening component VGAU (represented by the parameter v b ), was also fitted. The broad component improves the fit by ∆C = 23, reducing the residuals at 22 Å (C = 2450 for 1545 d.o.f.…”

“…Mao et al (2018) found two narrow emission components explained this discrepancy as each had a different outflow velocity, with no influence on the geometry. In the case of NGC 3783, adding a broadened emission component significantly improved the fit by ∆C ∼ 200 (Mao et al 2019). For this reason, we applied the same approach to NGC 7469.…”

“…We have also calculated the distances of the emission line regions within NGC 5548 and NGC 3783, both analysed with PION, by Mao et al (2018) and Mao et al (2019), respectively, using Eq. (5) (for the narrow emission components C v = 0.1, and for the broad components C v = 0.001).…”

“…Di Gesu et al 2013;Whewell et al 2015). The emission line regions in Seyfert 1 AGN have been investigated in great detail in NGC 5548 (Whewell et al 2015;Mao et al 2018) and more recently in NGC 3783 (Mao et al 2019). In this paper, we focus on the emission line regions of NGC 7469 and measure, for the first time, their location with respect to the central black hole.…”