Mon. Not. R. Astron. Soc., 437, 3929-3938 (2014/February-1)
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. and LOBBAN A.P.
Abstract (from CDS):
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 7yr 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.
© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2013)
galaxies: individual: RE J2248-511 - galaxies: Seyfert
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