Anatomy of the AGN in NGC 5548 IX. photoionized emission features in the soft X-ray spectra

Tools

Mao, Junjie and Kaastra, J. S. and Mehdipour, M. and Gu, Liyi and Costantini, E. and Kriss, G. A. and Bianchi, S. and Branduardi-Raymont, G. and Behar, E. and Gesu, L. Di and Ponti, G. and Petrucci, P. -O. and Ebrero, J. (2018) Anatomy of the AGN in NGC 5548 IX. photoionized emission features in the soft X-ray spectra. Astronomy and Astrophysics, 612. A18. ISSN 0004-6361 (https://doi.org/10.1051/0004-6361/201732162)

[thumbnail of Mao-etal-AA2018-Anatomy-AGN-NGC-5548-IX-photoionized-emission-features-soft-X-ray-spectra]
Preview
 Text. Filename: Mao_etal_AA2018_Anatomy_AGN_NGC_5548_IX_photoionized_emission_features_soft_X_ray_spectra.pdf
Accepted Author Manuscript
Download (1MB)| Preview

Abstract

The X-ray narrow emission line region (NELR) of the archetypal Seyfert 1 galaxy NGC\,5548 has been interpreted as a single-phase photoionized plasma that is absorbed by some of the warm absorber components. This scenario requires those overlaying warm absorber components to have larger distance (to the central engine) than the X-ray NELR, which is not fully consistent with the distance estimates found in the literature. Therefore, we reanalyze the high-resolution spectra obtained in 2013--2014 with the Reflection Grating Spectrometer (RGS) aboard \textit{XMM}-Newton to provide an alternative interpretation of the X-ray narrow emission features. We find that the X-ray narrow emission features in NGC\,5548 can be described by a two-phase photoionized plasma with different ionization parameters ($\log \xi=1.3$ and $0.1$) and kinematics ($v_{\rm out}=-50$ and $-400~{\rm km~s^{-1}}$), and no further absorption by the warm absorber components. The X-ray and optical NELR might be the same multi-phase photoionized plasma. Both X-ray and optical NELR have comparable distances, asymmetric line profiles, and the underlying photoionized plasma is turbulent and compact in size. The X-ray NELR is not the counterpart of the UV/X-ray absorber outside the line of sight because their distances and kinematics are not consistent. In addition, X-ray broad emission features that we find in the spectrum can be accounted for by a third photoionized emission component. The RGS spectrum obtained in 2016 is analyzed as well, where the luminosity of most prominent emission lines (the \ion{O}{vii} forbidden line and \ion{O}{viii} Ly$\alpha$ line) are the same (at a 1 $\sigma$ confidence level) as in 2013--2014.

ORCID iDs

Mao, Junjie ORCID logoORCID: https://orcid.org/0000-0001-7557-9713, Kaastra, J. S., Mehdipour, M., Gu, Liyi, Costantini, E., Kriss, G. A., Bianchi, S., Branduardi-Raymont, G., Behar, E., Gesu, L. Di, Ponti, G., Petrucci, P. -O. and Ebrero, J.;
  • Item type:Article
    ID code:70842
    Dates:
    Date
    Event
    10 April 2018
    Published
    10 April 2018
    Published Online
    20 December 2017
    Accepted
    Subjects:Science > Astronomy
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:12 Dec 2019 12:42
    Last modified:11 Nov 2024 12:31
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/70842
CORE (COnnecting REpositories)