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Is there a UV/X-ray connection in IRAS 13224−3809?

Buisson, D. J. K. and Lohfink, A. M. and Alston, W. N. and Cackett, E. M. and Chiang, C.-Y. and Dauser, T. and De Marco, B. and Fabian, A. C. and Gallo, L. C. and García, J. A. and Jiang, J. and Kara, E. and Middleton, M. J. and Miniutti, G. and Parker, M. L. and Pinto, C. and Uttley, P. and Walton, D. J. and Wilkins, D. R. (2018) Is there a UV/X-ray connection in IRAS 13224−3809? Monthly Notices of the Royal Astronomical Society, 475 (2). pp. 2306-2313. ISSN 0035-8711.

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We present results from the optical, ultraviolet, and X-ray monitoring of the NLS1 galaxy IRAS 13224−3809 taken with Swift and XMM–Newton during 2016. IRAS 13224−3809 is the most variable bright AGN in the X-ray sky and shows strong X-ray reflection, implying that the X-rays strongly illuminate the inner disc. Therefore, it is a good candidate to study the relationship between coronal X-ray and disc UV emission. However, we find no correlation between the X-ray and UV flux over the available ∼40 d monitoring, despite the presence of strong X-ray variability and the variable part of the UV spectrum being consistent with irradiation of a standard thin disc. This means either that the X-ray flux which irradiates the UV emitting outer disc does not correlate with the X-ray flux in our line of sight and/or that another process drives the majority of the UV variability. The former case may be due to changes in coronal geometry, absorption or scattering between the corona and the disc.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Alston, W. N.0000-0003-2658-6559
Cackett, E. M.0000-0002-8294-9281
Chiang, C.-Y.0000-0002-9630-4003
Dauser, T.0000-0003-4583-9048
Fabian, A. C.0000-0002-9378-4072
García, J. A.0000-0003-3828-2448
Jiang, J.0000-0002-8796-5846
Kara, E.0000-0003-0172-0854
Middleton, M. J.0000-0002-8183-2970
Parker, M. L.0000-0002-8466-7317
Pinto, C.0000-0003-2532-7379
Walton, D. J.0000-0001-5819-3552
Additional Information:© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 December 22. Received 2017 December 18; in original form 2017 October 2. Published: 05 January 2018. We thank the referee for comments which have helped to improve the clarity of the paper. DJKB acknowledges financial support from the Science and Technology Facilities Council (STFC). ACF, AML, and MLP acknowledge support from the ERC Advanced Grant FEEDBACK 340442. BDM acknowledges support from the Polish National Science Center grant Polonez 2016/21/P/ST9/04025. This work has made use of observations obtained with XMM–Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
European Research Council (ERC)340442
National Science Centre (Poland)2016/21/P/ST9/04025
Subject Keywords:accretion, accretion discs – black hole physics – galaxies: individual: IRAS13224−3809 – galaxies: Seyfert
Issue or Number:2
Record Number:CaltechAUTHORS:20180329-144301332
Persistent URL:
Official Citation:D J K Buisson, A M Lohfink, W N Alston, E M Cackett, C-Y Chiang, T Dauser, B De Marco, A C Fabian, L C Gallo, J A García, J Jiang, E Kara, M J Middleton, G Miniutti, M L Parker, C Pinto, P Uttley, D J Walton, D R Wilkins; Is there a UV/X-ray connection in IRAS 13224−3809?, Monthly Notices of the Royal Astronomical Society, Volume 475, Issue 2, 1 April 2018, Pages 2306–2313,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85507
Deposited By: Tony Diaz
Deposited On:29 Mar 2018 21:52
Last Modified:17 Dec 2019 21:49

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