We present Chandra observations of the radio-quiet Broad Absorption Line (BAL) QSO PG 1254+047. We find that it is a weak X-ray source, with a total of 44 ± 7 photons measured in 36 ksec across the observed energy range 0.7 − 6.0 keV. Its X-ray weakness is consistent with the known correlation between αox and the strength of the UV absorption lines. The spectral energy distribution suggests tha...

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 Å U bands. We found a significant correlation peak at a time lag of τmax ∼ 160 ks where the UV flux variations preceded the variations in the X-ray band. We interpret this result as evidence in favour of Comptonisation models where the observ...

Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a dif...

A search for reprocessed X-rays causing UV pulsations in the companion stars to X-ray pulsars was carried out in a 200 Å wide bandpass centered at 1450 Å using the High Speed Photometer on theHubble Space Telescope.We observed the systems A0535+26 = HD245770, 4U0900-40 (Vela XR-1) = HD77581, A1118-61 = He3-640, and 4U1145-619 = HD102567. We confirm the existence of reprocessed X-rays reported i...

Abstract We present the first catalog of supernova remnants (SNRs) in M31 that exhibit diffuse ultraviolet (UV) emission. UV images were obtained by Ultraviolet Imaging Telescope (UVIT) on AstroSat satellite, and list SNRs was from X-ray, optical, radio catalogs M31. used UVIT to find with emission, omitting those too contaminated stellar A total 20 detected Fluxes F148W, F169M, F172M, N219M, N...

We explore the effects of UV absorbing material on the shape of the EUV continuum radiation emitted by the active galactic nucleus, and on the relative strengths of emission lines, formed in the narrow line regions of Seyfert galaxies, excited by this continuum. Within a sample of Seyfert 1.5 galaxies, objects with flatter soft X-ray slopes tend to have lower values of He II λ4686/Hβ, which imp...

We present a unified model for optical, ultraviolet (UV), and X-ray light curves of V1974 Cygni (Nova Cygni 1992). Based on an optically thick wind model of nova outbursts, we have calculated light curves and searched for the best fit model that is consistent with optical, UV, and X-ray observations. Our best fit model is a white dwarf (WD) of mass 1.05 M⊙ with a chemical composition of X = 0.4...

We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and γ -ray bands, on timescales down to 6–12 hr. The brightest γ -ray isotropic luminosity, recorded on 2009 March...