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The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average

Starling, R.L.C.; Done, C.; Jin, C.; Romero-Colmenero, E.; Potter, S.B.; Wiersema, K.; Page, K.L.; Page, M.J.; Breeveld, A.A.; Lobban, A.P.

The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average Thumbnail


R.L.C. Starling

C. Jin

E. Romero-Colmenero

S.B. Potter

K. Wiersema

K.L. Page

M.J. Page

A.A. Breeveld

A.P. Lobban


RE J2248−511 is one of only 14 non-blazar active galactic nuclei (AGN) detected in the far-ultraviolet (FUV) by the ROSAT Wide Field Camera implying a large ultrasoft X-ray flux. This soft X-ray excess is strongly variable on year time-scales, a common property of narrow-line Seyfert 1s, yet its optical line widths classify this source as a broad-lined Seyfert 1 (BLS1). We use four nearly simultaneous optical–X-ray spectral energy distributions (SEDs) spanning 7 yr to study the spectral shape and long-term variability of RE J2248−511. Here we show that the continuum SED for the brightest epoch data set is consistent with the mean SED of a standard quasar, and matches well to that from an XMM–Sloan Digital Sky Survey sample of AGN with 〈M/M⊙〉 ∼ 108 and 〈L/LEdd〉 ∼ 0.2. All the correlated optical and soft X-ray variability can be due entirely to a major absorption event. The only remarkable aspect of this AGN is that there is no measurable intrinsic X-ray absorption column in the brightest epoch data set. The observed FUV flux is determined by the combination of this and the fact that the source lies within a local absorption ‘hole’. RE J2248−511, whose variable, ultrasoft X-ray flux once challenged its BLS1 classification, demonstrates that characterization of such objects requires multi-epoch, multiwavelength campaigns.


Starling, R., Done, C., Jin, C., Romero-Colmenero, E., Potter, S., Wiersema, K., …Lobban, A. (2014). The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average. Monthly Notices of the Royal Astronomical Society, 437(4), 3929-3938.

Journal Article Type Article
Acceptance Date Nov 9, 2013
Online Publication Date Dec 6, 2013
Publication Date Feb 1, 2014
Deposit Date Mar 16, 2016
Publicly Available Date Mar 18, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 437
Issue 4
Pages 3929-3938
Related Public URLs


Published Journal Article (946 Kb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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