The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Anomalous behaviour of the UV-optical continuum bands in NGC 5548

Anomalous behaviour of the UV-optical continuum bands in NGC 5548
Anomalous behaviour of the UV-optical continuum bands in NGC 5548
During the 2014 HST/Swift and ground-based multi-wavelength monitoring campaign of NGC 5548 (AGN STORM), the UV-optical broad emission lines exhibited anomalous, decorrelated behaviour relative to the far-UV continuum flux variability. Here, we use key diagnostic emission lines (Ly-alpha and He II) for this campaign to infer a proxy for the all important, variable driving EUV continuum incident upon BLR clouds. The inferred driving continuum provides a crucial step towards the recovery of the broad emission line response functions in this AGN. In particular, the ionising continuum seen by the BLR was weaker and softer during the anomalous period than during the first third of the campaign, and apparently less variable than exhibited by the far-UV continuum. We also report the first evidence for anomalous behaviour in the longer wavelength (relative to 1157A) continuum bands. This is corroborative evidence that a significant contribution to the variable UV-optical continuum emission arises from a diffuse continuum emanating from the same gas that emits the broad emission lines.
astro-ph.GA
0035-8711
5362-5376
Goad, M. R.
9c241b66-bab0-487c-82c2-fe03162a9567
Knigge, C.
ac320eec-631a-426e-b2db-717c8bf7857e
Korista, K. T.
586b39a9-4942-4d95-9a13-7b922029864e
Cackett, E.
d14dd97a-9acb-4cf2-b9a7-17f9791fdee0
Horne, K.
53fcebf2-d0a1-453a-b141-6174ac5e4afe
Starkey, D. A.
d5e97df3-68ed-49ee-ad46-e6370ca618c5
Peterson, B. M.
ced340e7-3232-477e-bf0a-822a7fe67c92
Rosa, G. De
ba80f646-a47e-4bec-9c9e-807d01d99401
Kriss, G. A.
f55dc1eb-e1d5-4303-a99b-10bf3c87c0db
Edelson, R.
d2d130b6-1d4f-4fca-900f-26bc018a5b34
Fausnaugh, M.
cfddf3bf-5915-45cc-8597-e27e496dfa60
Goad, M. R.
9c241b66-bab0-487c-82c2-fe03162a9567
Knigge, C.
ac320eec-631a-426e-b2db-717c8bf7857e
Korista, K. T.
586b39a9-4942-4d95-9a13-7b922029864e
Cackett, E.
d14dd97a-9acb-4cf2-b9a7-17f9791fdee0
Horne, K.
53fcebf2-d0a1-453a-b141-6174ac5e4afe
Starkey, D. A.
d5e97df3-68ed-49ee-ad46-e6370ca618c5
Peterson, B. M.
ced340e7-3232-477e-bf0a-822a7fe67c92
Rosa, G. De
ba80f646-a47e-4bec-9c9e-807d01d99401
Kriss, G. A.
f55dc1eb-e1d5-4303-a99b-10bf3c87c0db
Edelson, R.
d2d130b6-1d4f-4fca-900f-26bc018a5b34
Fausnaugh, M.
cfddf3bf-5915-45cc-8597-e27e496dfa60

Goad, M. R., Knigge, C., Korista, K. T., Cackett, E., Horne, K., Starkey, D. A., Peterson, B. M., Rosa, G. De, Kriss, G. A., Edelson, R. and Fausnaugh, M. (2019) Anomalous behaviour of the UV-optical continuum bands in NGC 5548. Monthly Notices of the Royal Astronomical Society, 486 (4), 5362-5376. (doi:10.1093/mnras/stz1186).

Record type: Article

Abstract

During the 2014 HST/Swift and ground-based multi-wavelength monitoring campaign of NGC 5548 (AGN STORM), the UV-optical broad emission lines exhibited anomalous, decorrelated behaviour relative to the far-UV continuum flux variability. Here, we use key diagnostic emission lines (Ly-alpha and He II) for this campaign to infer a proxy for the all important, variable driving EUV continuum incident upon BLR clouds. The inferred driving continuum provides a crucial step towards the recovery of the broad emission line response functions in this AGN. In particular, the ionising continuum seen by the BLR was weaker and softer during the anomalous period than during the first third of the campaign, and apparently less variable than exhibited by the far-UV continuum. We also report the first evidence for anomalous behaviour in the longer wavelength (relative to 1157A) continuum bands. This is corroborative evidence that a significant contribution to the variable UV-optical continuum emission arises from a diffuse continuum emanating from the same gas that emits the broad emission lines.

Text
1904.12588v1 - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 25 April 2019
Published date: 29 April 2019
Keywords: astro-ph.GA

Identifiers

Local EPrints ID: 430931
URI: http://eprints.soton.ac.uk/id/eprint/430931
ISSN: 0035-8711
PURE UUID: f38fb5bb-57c5-4db7-9b83-3640f6dfd18a

Catalogue record

Date deposited: 17 May 2019 16:30
Last modified: 25 Nov 2021 20:25

Export record

Altmetrics

Contributors

Author: M. R. Goad
Author: C. Knigge
Author: K. T. Korista
Author: E. Cackett
Author: K. Horne
Author: D. A. Starkey
Author: B. M. Peterson
Author: G. De Rosa
Author: G. A. Kriss
Author: R. Edelson
Author: M. Fausnaugh

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×