Search Publications
Evolution of magnetic fields in stars across the upper main sequence: I. Catalogue of magnetic field measurements with FORS 1 at the VLT
Hubrig, S.; North, P.; Schöller, M. +1 more
To properly understand the physics of Ap and Bp stars it is particularly important to identify the origin of their magnetic fields. For that, an accurate knowledge of the evolutionary state of stars that have a measured magnetic field is an important diagnostic. Previous results based on a small and possibly biased sample suggest that the distribu…
Statistics of relativistically broadened Fe Kα lines in AGN
Bianchi, S.; Guainazzi, M.; Dovčiak, M.
We present preliminary results on the properties of relativistically broadened Fe Kα lines in a collection of more then 100 Active Galactic Nuclei (AGN) observed by the XMM-Newton EPIC-pn camera. Our main conclusions can be summarized as follows: a) we detect broad lines in about 25% of the sample objects. This fraction increases to 42 ± 13 % if w…
Relativistic blue- and red-shifted absorption lines in AGNs
Cappi, M.
Current, accumulating evidence for (mildly) relativistic blue- and red-shifted absorption lines in AGNs is reviewed. XMM-Newton and Chandra sensitive X-ray observations are starting to probe not only the kinematics (velocity) but also the dynamics (accelerations) of highly ionized gas flowing in-and-out from, likely, a few gravitational radii from…
Suzaku observations of iron lines and reflection in AGN
Kataoka, J.; Fabian, A. C.; Takahashi, T. +8 more
Initial results on the iron K-shell line and reflection component in several AGN observed as part of the Suzaku Guaranteed Time program are reviewed. This paper discusses a small sample of Compton-thin Seyferts observed to date with Suzaku; namely MCG -5-23-16, MCG -6-30-15, NGC 4051, NGC 3516, NGC 2110, 3C 120 and NGC 2992. The broad iron K\alpha…
V4332 Sgr in `Quiescence'
Kimeswenger, S.
In 1994 V4332 Sgr underwent a mysterious eruption. Somehow its fast evolution towards a red giant star was, lacking alternative classifications, connected to the red variable M31 RV, which had its eruption in 1988. The red eruptive variable V838 Mon draw the attention back to its 'older twin' V4332 Sgr in February 2002. The new precise photometry …
An XMM-Newton survey of broad iron lines in AGN
Nandra, K.; Turner, T. J.; Reeves, J. N. +2 more
We report on the iron Kα line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM-Newton spectra. Once appropriate soft X-ray absorption, narrow 6.4 keV emission and associated Compton reflection are acc…
New radio halos and relics in clusters of galaxies
Govoni, F.; Giovannini, G.; Pizzo, R. +2 more
We present here new images of relics and halo sources in rich cluster of galaxies and the correlation between the halo radio surface brightness versus the cluster bolometric X-ray luminosity.
A short review of relativistic iron lines from stellar-mass black holes
Miller, J. M.
% In this contribution, I briefly review recent progress in detecting and measuring the properties of relativistic iron lines observed in stellar-mass black hole systems, and the aspects of these lines that are most relevant to studies of similar lines in Seyfert-1 AGN. In particular, the lines observed in stellar-mass black holes are not complica…
A short introduction to broad and variable iron lines around black holes
Fabian, A. C.
Accreting black holes often show iron line emission in their X-ray spectra. When this line emission is very broad or variable then it is likely to originate from close to the black hole. The theory and observations of such broad and variable iron lines are briefly reviewed here. In order for a clear broad line to be found, one or more of the follo…
High redshift Lyα halos
De Breuck, C.; van Breugel, W.; Croft, S. +5 more
We review current evidence for the existence of large emission-line halos around high redshift radio galaxies. Detailed narrow-band imaging and spectroscopic studies of these systems may help us understand the early stages of massive forming galaxies and AGN feedback.