Fe III emission in quasars : evidence for a dense turbulent medium

Tools

Temple, Matthew J and Ferland, Gary J and Rankine, Amy L and Hewett, Paul C and Badnell, N R and Ballance, Connor P and Del Zanna, Giulio and Dufresne, Roger P (2020) Fe III emission in quasars : evidence for a dense turbulent medium. Monthly Notices of the Royal Astronomical Society, 496 (3). pp. 2565-2576. ISSN 0035-8711 (https://doi.org/10.1093/mnras/staa1717)

[thumbnail of Temple-etal-MNRAS-2020-Fe-III-emission-in-quasars]
Preview
 Text. Filename: Temple_etal_MNRAS_2020_Fe_III_emission_in_quasars.pdf
Accepted Author Manuscript
Download (1MB)| Preview

Abstract

Recent improvements to atomic energy-level data allow, for the first time, accurate predictions to be made for the Fe III line emission strengths in the spectra of luminous, Lbol≃1046−1048ergs−1⁠, active galactic nuclei. The Fe III emitting gas must be primarily photoionized, consistent with observations of line reverberation. We use CLOUDY models exploring a wide range of parameter space, together with ≃26 000 rest-frame ultraviolet spectra from the Sloan Digital Sky Survey, to constrain the physical conditions of the line emitting gas. The observed Fe III emission is best accounted for by dense (nH ≃ 1014 cm−3) gas which is microturbulent, leading to smaller line optical depths and fluorescent excitation. Such high density gas appears to be present in the central regions of the majority of luminous quasars. Using our favoured model, we present theoretical predictions for the relative strengths of the Fe III UV34 λλ1895, 1914, 1926 multiplet. This multiplet is blended with the Si III] λ1892 and C III] λ1909 emission lines and an accurate subtraction of UV34 is essential when using these lines to infer information about the physics of the broad line region in quasars.

ORCID iDs

Temple, Matthew J, Ferland, Gary J, Rankine, Amy L, Hewett, Paul C, Badnell, N R ORCID logoORCID: https://orcid.org/0000-0001-7418-7996, Ballance, Connor P, Del Zanna, Giulio and Dufresne, Roger P;
  • Item type:Article
    ID code:73898
    Dates:
    Date
    Event
    31 August 2020
    Published
    17 June 2020
    Published Online
    12 June 2020
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:17 Sep 2020 10:42
    Last modified:20 Nov 2024 09:44
    URI:https://strathprints.strath.ac.uk/id/eprint/73898
CORE (COnnecting REpositories)