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

Starling, R.L.C. and Done, C. and Jin, C. and Romero-Colmenero, E. and Potter, S.B. and Wiersema, K. and Page, K.L. and Page, M.J. and Breeveld, A.A. and Lobban, A.P. (2014) 'The story of Seyfert galaxy RE J2248-511 : from intriguingly ultrasoft to unremarkably average.', Monthly notices of the Royal Astronomical Society., 437 (4). pp. 3929-3938.

Abstract

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.

Item Type:Article
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Status:Peer-reviewed
Publisher Web site:http://dx.doi.org/10.1093/mnras/stt2201
Publisher 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.
Date accepted:09 November 2013
Date deposited:18 March 2016
Date of first online publication:06 December 2013
Date first made open access:No date available

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