SIMBAD references

2011MNRAS.414.3307G - Mon. Not. R. Astron. Soc., 414, 3307-3321 (2011/July-2)

A broad-band X-ray view of the warm absorber in radio-quiet quasar MR 2251-178.

GOFFORD J., REEVES J.N., TURNER T.J., TOMBESI F., BRAITO V., PORQUET D., MILLER L., KRAEMER S.B. and FUKAZAWA Y.

Abstract (from CDS):

We present the analysis of a new broad-band X-ray spectrum (0.6–180.0 keV) of the radio-quiet quasar MR 2251-178 which uses both Suzaku and Swift/Burst Alert Telescope data. In accordance with previous observations, we find that the general continuum can be well described by a power law with Γ= 1.6 and an apparent soft excess below 1 keV. Warm absorption is clearly present, and absorption lines due to the Fe unresolved transition array, Fe L (Fe XXIII–XXIV), S XV and S XVI are detected below 3 keV. At higher energies, Fe K absorption from Fe XXV–XXVI is detected and a relatively weak (EW = 25+12–8eV) narrow Fe Kα emission line is observed (E= 6.44±0.04 keV) which is well modelled by the presence of a mildly ionized (ξ≲ 30) reflection component with a low reflection fraction (R < 0.2). At least five ionized absorption components with 1020NH≲ 1023/cm2 and 0 ≲ log ξ/erg cm/s≲ 4 are required to achieve an adequate spectral fit. Alternatively, we show that the continuum can also be fit if a Γ∼ 2.0 power law is absorbed by a column of NH∼ 1023/cm2 which covers ∼30 per cent of the source flux. Independent of which continuum model is adopted, the Fe L and Fe XXV Heα lines are well fit by a single absorber outflowing with vout∼ 0.14c. Such an outflow/disc-wind is likely to be substantially clumped (b∼ 10–3) in order to not vastly exceed the likely accretion rate of the source.

Abstract Copyright: 2011 The Authors Monthly Notices of the Royal Astronomical Society2011 RAS

Journal keyword(s): galaxies: active - galaxies: individual: MR 2251-178 - X-rays: galaxies

Simbad objects: 12

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