We model the correlated X-ray – UV observations of NGC 7469, for which well sampled data in both these bands have been obtained recently in a multiwavelength monitoring campaign. To this end we derive the transfer function in wavelength λ and time lag τ , for reprocessing hard (X-ray) photons from a point source to softer ones (UV-optical) by an infinite plane (representing a cool, thin accreti...

We analyze a composite broad-band optical/UV/Xγ-ray spectrum of the Seyfert 1 galaxy NGC 5548. The spectrum consists of an average of simultaneous optical/IUE/Ginga observations accompanied by ROSAT and GRO/OSSE data from non-simultaneous observations. We show that the broad-band continuum is inconsistent with simple disk models extending to the soft X-rays. Instead, the soft-excess is well des...

The width of the broad Hβ emission line is the primary defining characteristic of the NLS1 class. This parameter is also an important component of Boroson and Green’s optical “Eigenvector 1”(EV1), which links steeper soft X-ray spectra with narrower Hβ emission, stronger Hβ blue wing, stronger optical Fe II emission, and weaker [O III]λ5007. Potentially, EV1 represents a fundamental physical pr...

We analyse 15 XMM–Newton observations of the Seyfert galaxy NGC 4051 obtained over 45 d to determine the ultraviolet (UV) light curve variability characteristics and search for correlated UV/X-ray emission. The UV light curve shows variability on all time-scales, however with lower fractional rms than the 0.2–10 keV X-rays. On days–weeks time-scales the fractional variability of the UV is Fvar ...

UV-vis spectroscopy was used in a combined in-situ UV-vis/XAFS spectroscopic setup to study the synchrotron radiation effect on aqueous homogeneous copper solutions. Two different systems were studied. In the first study, the focus was on a copper bipyridine-catalyzed oxidation of benzyl alcohol to benzaldehyde with 2,2,6,6- tetramethylpiperidinyl-1-oxy and base as cocatalysts. It was found tha...

The unified picture of X-ray/UV absorbers offers an unique opportunity to probe the nuclear environment of AGNs. To test the unified absorber scenario and to understand the physical properties of the absorber we obtained the first UV spectrum of PG1114+445 using HST FOS. PG1114+445 is known to have an X-ray ionized (“warm”) absorber, so that UV absorption is predicted. The HST spectrum clearly ...

We study the UV properties of Type I AGN from the ROSAT All-Sky Survey that have been selected to show unusually soft X-ray continua. We examine a sample of 54 Seyfert 1 galaxies with detections in both the GALEX Near-UV and Far-UV bands and look for correlations between their UV and X-ray properties. We also search for correlations of these properties with either black hole mass or Eddington r...

Well-aligned Cu-doped ZnO nanorods were successfully synthesized on polyethylene terephthalate (PET) substrate using chemical bath deposition method. The structural and optical properties of Cu-doped ZnO nanorods were investigated using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence (PL) spectroscopy...

Context. Classical T Tauri stars are young solar-type stars accreting material from their circumstellar disks. Thanks to a favorable inclination of the system, the classical T Tauri star AA Tau exhibits periodic optical eclipses as the warped inner disk edge occults the stellar photosphere. Aims. We intend to observe the X-ray and UV emission of AA Tau during the optical eclipses with the aim t...

We report results from the spectral analysis of pointed ROSAT PSPC observations of six PG quasars and the weak-bump quasar PHL 1657. Disregarding other frequency bands, the PSPC data are represented best by simple power-law source spectra (dN=dE / EΓ) with a slope Γ = 2:5 0:4 and do not show evidence for a more complex structure. However, within the limits given by statistics and systematical e...