相关论文: Is the soft excess in AGN real?
The origin of the soft excess seen in many AGN below ~1 keV is still an unsolved problem. It is unlikely to represent a true continuum component as its characteristic 'temperature' shows a remarkable constancy over a wide range of AGN…
The nature and origin of the soft X-ray excess in radio quiet AGN is still an open issue. The interpretation in terms of thermal disc emission has been challanged by the discovery of the constancy of the effective temperature despite the…
We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line Seyfert 1 galaxy, 1H 0707-495, which has…
We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line Seyfert 1 galaxy, 1H 0707-495, which has…
We have observed with XMM-Newton four radiatively efficient active type 1 galaxies with black hole masses < 10^6 Msun, selected optically from the SDSS. We show here that their soft X-ray spectrum exhibits a soft excess with the same…
In this paper we examine the percentage of type 1 AGN which require the inclusion of a soft excess component and/or significant cold absorption in the modelling of their X-ray spectra obtained by XMM-Newton. We do this by simulating spectra…
The soft excess seen in many AGN is most probably due to partially ionized material moving at relativistic speeds close to the black hole. There are currently two potential geometries for this material, one where it is out of the line of…
We discuss the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised material rather than where it is a true continuum component. However, current data…
We present a large sample of type 1 AGN spectra taken with XMM-Newton. We fit them with the relativistically blurred photoionized disc model of Ross & Fabian (2005). This model is based on an illuminated accretion disc of fluorescing and…
An excess of X-ray emission below 1 keV, called soft excess, is detected in a large fraction of Seyfert 1-1.5s. The origin of this feature remains debated, as several models have been suggested to explain it, including warm Comptonization…
We discuss various ideas for the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised rather than where it is a true continuum component. However,…
XMM-Newton observations of seven QSOs are presented and the EPIC spectra analysed. Five of the AGN show evidence for Fe K-alpha emission, with three being slightly better fitted by lines of finite width; at the 99 per cent level they are…
Strong soft X-ray emission called soft X-ray excess is often observed in luminous active galactic nuclei (AGN). It has been suggested that the soft X-rays are emitted from a warm ($T=10^6\sim10^7\ \rm{K}$) region that is optically thick for…
A series of nine XMM-Newton observations of the radio-loud quasar 3C 273 are presented, concentrating mainly on the soft excess. Although most of the individual observations do not show evidence for iron emission, co-adding them reveals a…
The UV to X-ray continuum of active galactic nuclei (AGN) is important for maintaining the ionisation and thermal balance of the warm absorbers (WAs). However, the spectra in the sensitive energy range $\sim \,13.6 -300 \ev$ are…
The X-ray spectra of many active galactic nuclei (AGN) show a soft X-ray excess below 1-2 keV on top of the extrapolated high- energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred,…
The X-ray spectra of many active galactic nuclei (AGN) exhibit a `soft excess' below 1keV, whose physical origin remains unclear. Diverse models have been suggested to account for it, including ionised reflection of X-rays from the inner…
This paper discusses the properties of scattering--dominated active galactic nuclei (AGN). We define these to be AGN for which the direct line-of-sight to the continuum source is obscured by Compton-thick material. The aim is to construct,…
Although soft X-ray absorption features in AGN were discovered almost ten years ago, the nature and location of the gas creating them has remained controversial. However, by making use of the newly-available high-resolution spectra provided…
We present a detailed spectral analysis of the joint XMM-Newton and NuSTAR observations of the active galactic nuclei (AGN) in the Seyfert 1.5 Galaxy ESO 362-G18. The broadband ($0.3\mbox{--}79$ keV) spectrum shows the presence of a…