Related papers: Correlated X-ray and Optical Variability in Mkn 50…
The narrow-line Seyfert 1 galaxy Markarian 766 was observed for 60 ks with the XMM-Newton observatory. The source shows a complex X-ray spectrum. The 2-10 keV spectrum can be adequately represented by a power law and broad Fe Ka emission.…
We present detailed broadband UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which…
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…
Using a month-long X-ray lightcurve from ${\it RXTE}$/PCA and 1.5 month long UV continuum lightcurves from ${\it IUE}$ spectra in 1220$-$1970 $\r{A}$, we performed a detailed time-lag study of the Seyfert 1 galaxy NGC 7469. Our…
This paper presents the results of a dense and intensive X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051 carried out in 2000. Results of the optical analysis are consistent with previous measurements. The amplitude…
We present the results of an intensive ground-based spectrophotometric monitoring campaign of the Seyfert galaxy NGC~4151 for a period of over two months, with a typical temporal resolution of one day. Light curves for four optical…
Radio-to-TeV observations of the bright nearby (z=0.034) blazar Markarian 501 (Mrk 501), performed from December 2012 to April 2018, are used to study the emission mechanisms in its relativistic jet. We examined the multi-wavelength…
We present X-ray observations of the Narrow-Line Seyfert 1 galaxy PKS 0558-504 obtained with RXTE during a 1-year monitoring campaign. This source, which is one of the very few radio-loud NLS1 galaxies, shows strong X-ray flux variability…
We present the light curves obtained during an eight-year program of optical spectroscopic monitoring of nine Seyfert 1 galaxies: 3C 120, Akn 120, Mrk 79, Mrk 110, Mrk 335, Mrk 509, Mrk 590, Mrk 704, and Mrk 817. All objects show…
We present the spectral analysis of an early XMM-Newton observation of the luminous Seyfert 1 galaxy Markarian 509. We find the hard (2-10 keV) continuum slope, including reflection, to be somewhat flatter ($\Gamma=1.75$) than for a typical…
We used a ~300 ks long XMM-Newton observation of the Seyfert 1 galaxy MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 A bands. We found a significant correlation peak at a time lag of 160 ks where the UV…
We present long term monitoring of MCG-6-30-15 in X-rays, optical and near-IR wavelengths, collected over five years of monitoring. We determine the power spectrum density of all the observed bands and show that after taking into account…
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 report on the largest Swift AGN monitoring program, concerning UV/optical variability in Seyferts. From 554 observations, over a 750d period, of the Seyfert galaxy NGC 5548, we see (McHardy et al. 2014) a good overall correlation between…
We present results from a recent broad-band monitoring in optics of the Seyfert 1 type galaxy Mrk 279. We build and analyse the BVRI light curve covering a period of seven years (1995 - 2002). We also show some evidence for the existence of…
We present an analysis of the X-ray time lags for the highly variable Seyfert 1 galaxy NGC 4051, based on a series of XMM-Newton observations taken in 2009. We investigate the Fourier frequency dependent time lags in the light curves…
We present the results of a continuum reverberation mapping study of the radio-quiet Seyfert 1 galaxy IRAS 09149-6206. The analysis was performed using X-ray, UV and optical observations made with the {\em Swift} telescope between January…
We report on the XMM-Newton timing properties of the most X-ray variable, radio-quiet, NLS1 IRAS 13224-3809. IRAS 13224-3809 continues to display the extremely variable behavior that was previously observed with ROSAT and ASCA; however, no…
We present results from a multi-year monitoring campaign of the broad-line radio galaxy 3C 120, using the Rossi X-ray Timing Explorer (RXTE) for nearly five years of observations. Additionally, we present coincident optical monitoring using…
(Abridged) We present an analysis of a 10-day continuous ASCA observation of the narrow-line Seyfert 1 galaxy IRAS 13224-3809. The soft (0.7-1.3 keV) and hard (1.3-10 keV) X-ray band light curves binned to 5000s reveal trough-to-peak…