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.

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.

Citation

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. https://doi.org/10.1093/mnras/stt2201

• 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
• DOI: https://doi.org/10.1093/mnras/stt2201
• Public URL: https://durham-repository.worktribe.com/output/1386004
• Related Public URLs: http://adsabs.harvard.edu/abs/2014MNRAS.437.3929S