Search Publications
An intrinsic source of reddening in the cataclysmic variable SS Cygni
Gaudenzi, S.; Giovannelli, F.; Lombardi, R. +2 more
By using the INES archive of the IUE satellite, we analyzed the spectra of SS Cygni in quiescence in order to determine the value of the reddening of the binary system. The reddening of the system is reported in the literature with values that vary significantly from one another. The results demonstrate that the reddening is comprised by two compo…
A photometric long-term study of chemically peculiar stars in open clusters
Fossati, L.; Heiter, U.; Paunzen, E. +5 more
Context. Photometric variability of chemically peculiar (CP) stars of the upper main sequence is closely connected to their local stellar magnetic field and their rotational period. Long term investigations, as presented here, help us to identify possible stellar cycles (as in the Sun). Furthermore, these data provide a basis for detailed surface …
The populations of hard X-ray and γ-ray sources: a correlation study and new possible identifications
Cusumano, G.; Tramacere, A.; La Parola, V. +4 more
Aims: We present the results of our analysis devoted to researching Galactic and extragalactic sources emitting in the energy bands surveyed by both the Swift-BAT and the Fermi-LAT telescopes.
Methods: We cross-correlated the Fermi-LAT 1-year point source catalogue (1FGL) of gamma-ray sources and the second Palermo BAT catalogue (2PBC) o…
VLT adaptive optics search for luminous substructures in the lens galaxy towards SDSS J0924+0219
Faure, C.; Meylan, G.; Courbin, F. +4 more
The anomalous flux ratios between quasar images are suspected of being caused by substructures in lens galaxies. We present new deep and high-resolution H and Ks imaging of the strongly lensed quasar SDSS J0924+0219 obtained using the ESO VLT with adaptive optics and the laser guide star system. SDSS J0924+0219 is particularly interesting because …
INTEGRAL observations of the GeV blazar PKS 1502+106 and the hard X-ray bright Seyfert galaxy Mkn 841
Maraschi, L.; Tagliaferri, G.; Ghisellini, G. +15 more
Context. Extragalactic nuclear activity is most effectively explored with observations at high energies, where the most extreme flux and spectral variations are expected to occur, because of changes in either the accretion flow or the kinematics of the plasma. In active galactic nuclei of blazar type, these variations are the most dramatic.
A…
A current sheet traced from the Sun to interplanetary space
Zhao, H.; Wang, J. X.; Wheatland, M. S. +2 more
Context. Magnetic reconnection is a central concept for understanding solar activity, including filament eruptions, flares, and coronal mass ejections (CMEs). The existence of transverse and vertical current sheets, sites where reconnection takes place in the solar atmosphere, is frequently proposed as a precondition for flare/CME models, but is r…
XMM-Newton observations of the X-ray soft polar QS Telescopii
Burwitz, V.; Dreizler, S.; Walter, F. M. +4 more
Context. On the basis of XMM-Newton observations, we investigate the energy balance of selected magnetic cataclysmic variables, which have shown an extreme soft-to-hard X-ray flux ratio in the ROSAT All-Sky Survey.
Aims: We intend to establish the X-ray properties of the system components, their flux contributions, and the accretion geometry …
STIS optical spectroscopy of the lobes of CRL 618
Velázquez, P. F.; Raga, A. C.; Riera, A. +2 more
Context. Many proto-planetary nebulae show collimated structures sometimes showing multiple outflows.
Aims: We present the results of new optical spectroscopic observations (both medium (with a dispersion of 0.56 Å pixel-1) and low (2.73 and 4.92 Å pixel-1 for the G430L and G750L gratings) spectral resolution) of the lob…
Stellar properties of z ~ 1 Lyman-break galaxies from ACS slitless grism spectra
Walsh, J. R.; Rosati, P.; Kümmel, M. +5 more
Lyman-break galaxies are now regularly found in the high redshift Universe by searching for the break in the galaxy spectrum caused by the Lyman-limit redshifted into the optical or even near-IR. At lower redshift, this break is covered by the GALEX UV channels and small samples of z ~ 1 LBGs have been presented in the literature. Here we give res…
Feasibility and performances of compressed sensing and sparse map-making with Herschel/PACS data
Sauvage, M.; Starck, J. -L.; Chanial, P. +2 more
The Herschel Space Observatory of ESA was launched in May 2009 and has been in operation ever since. From its distant orbit around L2, it needs to transmit a huge quantity of information through a very limited bandwidth. This is especially true for the PACS imaging camera, which needs to compress its data far more than what can be achieved with lo…