Modelling continuum reverberation in active galactic nuclei: a spectral-timing analysis of the ultraviolet variability through X-ray reverberation in Fairall 9

Author:

Hagen Scott1ORCID,Done Chris1

Affiliation:

1. Department of Physics, University of Durham , South Road, Durham DH1 3LE, UK

Abstract

ABSTRACT Continuum reverberation mapping of active galactic nuclei (AGNs) can provide new insight into the nature and geometry of the accretion flow. Some of the X-rays from the central corona irradiating the disc are absorbed, increasing the local disc temperature. This gives an additional reprocessed contribution to the spectral energy distribution (SED) which is lagged and smeared relative to the driving X-ray light curve. We directly calculate this reverberation from the accretion disc, creating fully time-dependent SEDs for a given X-ray light curve. We apply this to recent intensive monitoring data on Fairall 9, and find that it is not possible to produce the observed ultraviolet (UV) variability by X-ray reprocessing of the observed light curve from the disc. Instead, we find that the majority of the variability must be intrinsic to the UV emission process, adding to evidence from changing-look AGN that this region has a structure which is quite unlike a Shakura–Sunyaev disc. We filter out this long time-scale variability and find that reprocessing alone is still insufficient to explain even the fast variability in our assumed geometry of a central source illuminating a flat disc. The amplitude of reprocessing can be increased by any vertical structure such as the broad-line region and/or an inner disc wind, giving a better match. Fundamentally though the model is missing the major contributor to the variability, intrinsic to the UV/EUV emission rather than arising from reprocessing.

Funder

STFC

BEIS

Durham University

Publisher

Oxford University Press (OUP)

Subject

Space and Planetary Science,Astronomy and Astrophysics

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3