Blueshifted absorption lines from X-ray reflection in IRAS 13224−3809
We explore a disc origin for the highly blueshifted, variable absorption lines seen in the X-ray spectrum of the narrow-line Seyfert 1 galaxy IRAS 13224−3809. The blueshift corresponds to a velocity of ∼0.25c. Such features in other active galactic nuclei are often interpreted as ultrafast outflows. The velocity is of course present in the orbital motions of the inner disc. The absorption lines in IRAS 13224−3809 are best seen when the flux is low and the reflection component of the disc is strong relative to the power-law continuum. The spectra are consistent with a model in which the reflection component passes through a thin, highly ionized absorbing layer at the surface of the inner disc, the blueshifted side of which dominates the flux due to relativistic aberration (the disc inclination is about 70°). No fast outflow need occurs beyond the disc.
Additional Information© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Accepted 2020 February 14. Received 2020 February 14; in original form 2019 December 20. We thank the referee for helpful comments. WNA and ACF acknowledge support from ERC Advanced Grant FEEDBACK, 340442. JJ acknowledges support from the Tsinghua Astrophysics Outstanding Fellowship and the Tsinghua Shuimu Scholar Programme. JJ also acknowledges support from the Cambridge Trust and the Chinese Scholarship Council Joint Scholarship Programme (201604100032). CSR thanks the UK Science and Technology Facilities Council (STFC) for support under the New Applicant grant ST/R000867/1, and the European Research Council (ERC) for support under the European Union's Horizon 2020 research and innovation programme (grant 834203). PK acknowledges support from the STFC. BDM acknowledges support from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement no. 798726. GM acknowledges funding by the Spanish State Research Agency (AEI) Project No. ESP2017-86582-C4-1-R and No. MDM-2017-0737 Unidad de Excelencia 'María de Maeztu' – Centro de Astrobiología (CSIC-INTA).
Published - staa482.pdf
Accepted Version - 2002.06388.pdf