Related papers: Test for Echo: X-ray Reflection Variability in the…
We present an analysis of the narrow Fe K-alpha line in Chandra/HETGS observations of the Seyfert AGN, NGC 4151. The sensitivity and resolution afforded by the gratings reveal asymmetry in this line. Models including weak Doppler boosting,…
In the past five years, a flurry of X-ray reverberation lag measurements of accreting supermassive black holes have been made using the XMM-Newton telescope in the 0.3-10 keV energy range. In this work, we use the NuSTAR telescope to extend…
We report the Fe K relativistic reverberation feature for the first time in the Narrow-line Seyfert\,1 galaxy Ton\,S180. Using a long observation from {\it XMM-Newton} we find that the Fe K emission lag peaks at $117\pm49$ s in the lag…
X-rays illuminating the accretion disc in active galactic nuclei give rise to an iron K line and its associated reflection spectrum which are lagged behind the continuum variability by the light-travel time from the source to the disc. The…
We present Gemini/GNIRS spectroscopy of the Seyfert 2 galaxy NGC 4388, with simultaneous coverage from 0.85 - 2.5 $\mu$m. Several spatially-extended emission lines are detected for the first time, both in the obscured and unobscured portion…
Direct time-resolved spectral fitting has been performed on continuous RXTE monitoring of seven Seyfert 1 galaxies in order to study their broadband spectral variability and Fe K alpha variability characteristics on time scales of days to…
It has been suggested that X-ray observations of rapidly variable Seyfert galaxies may hold the key to probe the gas orbital motions in the innermost regions of accretion discs around black holes and, thus, trace flow patterns under the…
The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with…
We present results on the Seyfert 2 galaxy NGC4388 in the Virgo cluster observed with ASCA during its PV phase. The 0.5-10 keV X-ray spectrum consists of multiple components; (1) a continuum component heavily absorbed by a column density NH…
We use archival XMM-Newton observations of Ark 564 and Mrk 335 to calculate the frequency dependent time-lags for these two well-studied sources. We discover high-frequency Fe K lags in both sources, indicating that the red wing of the line…
Understanding disc-corona geometry through X-ray reverberation variability studies in Seyfert galaxies is crucial, yet our knowledge mostly relies on flux-averaged mean spectral analysis. In this study, we investigate the origin of the…
X-ray reverberation, where light-travel time delays map out the compact geometry around the inner accretion flow in supermassive black holes, has been discovered in several of the brightest, most variable and well-known Seyfert galaxies. In…
Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray…
We report on the X-ray time resolved spectral analysis of XMM-Newton observations of NGC 3783. The main goal is to detect transient features in the Fe K line complex, in order to study the dynamics of the innermost accretion flow. We…
Using new XMM-Newton observations we detect hard X-ray time lags in the rapid variability of the Compton-thin Seyfert 2 galaxy IRAS 18325-5926. The higher-energy X-ray variations lag behind correlated lower-energy variations by up to ~3ks…
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;…
Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in relatively high and low flux states, offer a unique opportunity to explore the complexity of its X-ray spectrum. We find the hard X-ray band to be significantly…
We report results from a Suzaku observation of the narrow-line Seyfert 1 NGC 4051. During our observation, large amplitude rapid variability is seen and the averaged 2--10 keV flux is 8.1x10^-12 erg s^-1 cm^-2, which is several times lower…
We present results from a joint Xmm-Newton/NuSTAR monitoring of the Seyfert 1 NGC 4593, consisting of 5x20 ks simultaneous observations spaced by two days, performed in January 2015. The source is variable, both in flux and spectral shape,…
The Seyfert 1 galaxy NGC 4593 was monitored spectroscopically with the Hubble Space Telescope as part of a reverberation mapping campaign that also included Swift, Kepler and ground-based photometric monitoring. During 2016 July 12 - August…