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|Title:||The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average|
|Authors:||Starling, R. L. C.|
Potter, S. B.
Page, K. L.
Page, M. J.
Breeveld, A. A.
Lobban, A. P.
|Publisher:||Oxford University Press (OUP), Royal Astronomical Society|
|Citation:||Monthly Notices of the Royal Astronomical Society, 2014, 437 (4), pp. 3929-3938 (10)|
|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.|
|Rights:||Archived with reference to SHERPA/RoMEO and publisher website. 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.|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
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