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

Junjie Mao, M. Mehdipour, J. S. Kaastra, E. Costantini, C. Pinto, G. Branduardi-Raymont, E. Behar, U. Peretz, S. Bianchi, G. A. Kriss, G. Ponti, B. De Marco, P. -O. Petrucci, L. Di Gesu, R. Middei, J. Ebrero, N. Arav

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Our Swift monitoring program triggered two joint XMM-Newton, NuSTAR, and HST observations on 11 and 21 December 2016 targeting NGC 3783 because 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 Reflection Grating Spectrometer (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.

Original languageEnglish
Article numberA99
Number of pages15
JournalAstronomy and Astrophysics
Issue numberA99
Publication statusPublished - 15 Jan 2019


  • X-rays: galaxies
  • galaxies: active
  • galaxies: Seyfert
  • galaxies: individual: NGC 3783
  • techniques: spectroscopic

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