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Intensive disc-reverberation mapping of Fairall 9 : 1st year of Swift & LCO monitoring

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journal contribution
posted on 08.09.2020, 17:03 by JV Hernández Santisteban, R Edelson, K Horne, JM Gelbord, AJ Barth, EM Cackett, MR Goad, H Netzer, D Starkey, P Uttley, WN Brandt, K Korista, AM Lohfink, CA Onken, KL Page, M Siegel, M Vestergaard, S Bisogni, AA Breeveld, SB Cenko, E Dalla Bontà, PA Evans, G Ferland, DH Gonzalez-Buitrago, D Grupe, MD Joner, G Kriss, SJ LaPorte, S Mathur, F Marshall, M Mehdipour, D Mudd, BM Peterson, T Schmidt, S Vaughan, S Valenti
We present results of time-series analysis of the first year of the Fairall 9 intensive disc-reverberation campaign. We used Swift and the Las Cumbres Observatory global telescope network to continuously monitor Fairall 9 from X-rays to near-infrared at a daily to sub-daily cadence. The cross-correlation function between bands provides evidence for a lag spectrum consistent with the τ ∝ λ4/3 scaling expected for an optically thick, geometrically thin blackbody accretion disc. Decomposing the flux into constant and variable components, the variable component's spectral energy distribution is slightly steeper than the standard accretion disc prediction. We find evidence at the Balmer edge in both the lag and flux spectra for an additional bound-free continuum contribution that may arise from reprocessing in the broad-line region. The inferred driving light curve suggests two distinct components, a rapidly variable (< 4 days) component arising from X-ray reprocessing, and a more slowly varying (> 100 days) component with an opposite lag to the reverberation signal.

History

Citation

Monthly Notices of the Royal Astronomical Society, Volume 498, Issue 4, November 2020, Pages 5399–5416, https://doi.org/10.1093/mnras/staa2365

Author affiliation

School of Chemistry

Version

AM (Accepted Manuscript)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

498

Issue

4

Pagination

5399-5416

Publisher

Oxford University Press (OUP) for Royal Astronomical Society

issn

0035-8711

eissn

1365-2966

Acceptance date

05/08/2020

Copyright date

2020

Available date

21/09/2020

Notes

The raw datasets were derived from sources in the public do-main: LCO archivehttps://archive.lco.globalandSwiftarchivehttps://www.swift.ac.uk/swift_live. The inter-calibrated light curves and Swift detector maps are avail-able in Zenodo, athttps://dx.doi.org/10.5281/zenodo.3956577.

Language

en