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Space Telescope and Optical Reverberation Mapping Project. XIII. An Atlas of UV and X-Ray Spectroscopic Signatures of the Disk Wind in NGC 5548

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posted on 2021-05-26, 11:03 authored by M Dehghanian, GJ Ferland, BM Peterson, GA Kriss, KT Korista, MR Goad, M Chatzikos, MC Bentz, F Guzman, M Mehdipour, G De Rosa
The unusual behavior of the spectral lines of NGC5548 during the STORM campaign demonstrated a missing piece in the structure of AGNs. For a two-month period in the middle of the campaign, the spectral lines showed a deficit in flux and a reduced response to the variations of the UV continuum. This was the first time that this behavior was unequivocally observed in an AGN. Our previous papers explained this as being due to a variable disk wind that acts as a shield and alters the SED. Here, we use Cloudy to create an atlas of photoionization models for a variety of disk winds, in order to study their effects on the SED. We show that the winds have three different cases: Case 1 winds are transparent, fully ionized, and have minimal effects on the intrinsic SED, although they can produce some line emission, especially He II or FeKα. We propose that this is the situation in most of the AGNs. Case 2 winds, which have a He++-He+ ionization front, block part of the XUV continuum but transmit much of the Lyman continuum. They lead to the observed abnormal behavior. Case 3 winds have a H+ ionization front and block much of the Lyman continuum. The results show that the presence of these winds has important effects on the spectral lines of AGNs. They will thus have an effect on the measurements of the black hole mass and the geometry of the AGN. This atlas of spectral simulations can serve as a guide to future reverberation campaigns.

History

Citation

The Astrophysical Journal, Volume 906, Number 1

Published in

The Astrophysical Journal

Volume

906

Issue

1

Publisher

IOP Publishing

issn

0004-637X

eissn

1538-4357

Acceptance date

2020-11-16

Copyright date

2020

Available date

2021-05-26

Language

English

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