Related papers: X-ray Variability Characteristics of the Seyfert 1…
By combining complementary monitoring observations spanning long, medium and short time scales, we have constructed power spectral densities (PSDs) of six Seyfert~1 galaxies. These PSDs span $\gtrsim$4 orders of magnitude in temporal…
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…
The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogeneous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from…
To investigate further the comparison between AGN and black hole X-ray binaries, we have studied the main X-ray variability properties of the Seyfert 1 Galaxy Markarian 335. We put particular emphasis on the X-ray time lags, which is a…
We present simultaneous X-ray and optical B and V band light curves of the Seyfert Galaxy NGC3783 spanning 2 years. The flux in all bands is highly variable and the fluctuations are significantly correlated. As shown before by Stirpe et al.…
We investigate the energy-time lag dependence of the source NGC 4593 using XMM-{\it Newton}/EPIC-pn data. We found that the time lag dependency is linear in nature with respect to the logarithm of different energy bands. We also investigate…
Active galactic nuclei (AGNs) exhibit strong variability across the electromagnetic spectrum on a wide range of timescales, particularly in X-rays where fluctuations are both rapid and high amplitude. Power spectral density (PSD) analysis…
This paper presents a comprehensive examination of the X-ray continuum variability of the bright Seyfert 1 galaxy MCG-6-30-15. The source clearly shows the strong, linear correlation between rms variability amplitude and flux first seen in…
We analyze observations of the Seyfert galaxy NGC 4151 covering 90 years in the optical band and 27 years in the 2-10 keV X-ray band. We compute the Normalized Power Spectrum Density (NPSD), the Structure Function (SF) and the…
During 1997 March-July, XTE observed the bright, strongly variable Seyfert 1 galaxy NGC 3516 once every ~12.8 hr for 4.5 months and nearly continuously (with interruptions due to SAA passage but not Earth occultation) for a 4.2 day period…
We present a detailed X-ray variability study of the low mass Active Galactic Nuclei (AGN) NGC 7314 using the two newly obtained XMM-Newton observations ($140$ and $130$ ks), together with two archival data sets of shorter duration ($45$…
We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions in 2005 with data obtained from an…
Data from the first three years of RXTE observations have been systematically analyzed to yield a set of 300 day, 2-10 keV light curves with similarly uniform, ~5 day sampling, for a total of nine Seyfert 1 galaxies. This is the first X-ray…
We present the results of our study of the long term X-ray variability characteristics of the Narrow Line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with the light curves obtained from XMM-Newton…
We present a detailed multi-frequency analysis of an intense monitoring programme of Seyfert 1 galaxy NGC 4593 over a duration of nearly for a month with Swift observatory. We used 185 pointings to study the variability in six…
We present a comprehensive examination of the X-ray variability of the narrow line Seyfert 1 (NLS1) galaxy NGC4051. We combine over 6.5 years of frequent monitoring observations by RXTE with a >100ks continuous observation by XMM-Newton and…
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…
We present a study of the time variability of NGC 7469, based on a ~30 d RXTE/PCA observation. Variability is seen across the X-ray band, and spectral changes are observed. The softness ratio is correlated with the ultraviolet flux, but…
The bright Seyfert 1 galaxy \mcg shows large variability on a variety of time scales. We study the $\aproxlt 3$ day time scale variability using a set of simultaneous archival observations that were obtained from \rxte and the {\it Advanced…
Beginning in 1999 January, the bright, strongly variable Narrow-Line Seyfert 1 (NLS1) galaxy Akn 564 has been observed by RXTE once every ~4.3 days. It was also monitored every ~3.2 hr throughout 2000 July. These evenly-sampled observations…