Search Publications
Solar Wind Particle Distribution Function Fitted via the Generalized Kappa Distribution Function: Cluster Observations
Lundin, R.; Balogh, A.; Dandouras, I. +17 more
One of the major issues in space plasma physics is that in spite of the inhomogeneity of interplanetary plasma and the complicated magnetic field topology we do not find strong deviations from Maxwellian distributions as it would be expected for a quasi-collisionless plasma. However, the presence of high energy tail and shoulders in the profile of…
Long-term monitoring of active stars. X. Photometry collected in 1994
Messina, S.; Rodonò, M.; Cutispoto, G.
As part of an extensive program focused on the global properties and evolution of active stars, high-precision UBV(RI)_c and UBV photometry of 18 selected stars is presented. UBV(RI)_c observations were collected at the European Southern Observatory over the intervals 21-28 September 1994 and 25 November-05 December 1994. Additional UBV photometry…
Time Series Photometry of Variable Stars in the Globular Cluster NGC 6397
Thompson, I. B.; Kaluzny, J.
Time series BVI photometry is presented for 16 short-period variables located in the central region of the globular cluster NGC 6397. The sample includes nine newly detected variables. The light curve of cataclysmic variable CV6 shows variability with a period of 0.2356 days. We confirm an earlier reported period of 0.472 days for cataclysmic vari…
INTEGRAL observations of SS433, a supercritically accreting microquasar with hard spectrum\thanks
Sunyaev, R. A.; Postnov, K. A.; Cherepashchuk, A. M. +3 more
Observations of SS433 by INTEGRAL carried out in March-May 2003 are presented. SS433 is evidently detected on the INTEGRAL images of the corresponding sky region in the energy bands 25-50 and 50-100 keV. The precessional variability of the hard X-ray flux is clearly seen. The X-ray eclipse caused by the binary orbital motion is also detected. A po…
Chandra LETGS and XMM-Newton observations of NGC 4593
Kaastra, J. S.; Behar, E.; Sako, M. +6 more
In this paper, we analyze spectra of the Seyfert 1 galaxy NGC 4593 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS), the Reflection Grating Spectrometer (RGS) and the European Photon Imaging Camera's (EPIC) onboard of XMM-Newton. The two observations were separated by ~ 7 months. In the LETGS spectrum we detect a high…
The Homogeneity of Interstellar Krypton in the Galactic Disk
Meyer, David M.; Cartledge, Stefan I. B.; Lauroesch, J. T.
We present an analysis of high-resolution Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) observations of Kr I λ1236 absorption in seven sight lines that probe a variety of interstellar environments. In combination with krypton and hydrogen column densities derived from current and archival STIS and Far-Ultraviolet Spectroscopic…
On variation of the latitudinal structure of the solar convection zone
Thompson, M. J.; Antia, H. M.; Chitre, S. M.
The latitudinal sound-speed structure of the Sun's convection zone gives insight into the physical processes occurring there, specifically the cellular convection and possibly the presence of magnetic fields. Using helioseismic data from the GONG network and MDI instrument on SOHO, we map the latitudinal acoustic structure of the convection zone f…
The dynamics of jovian white ovals from formation to merger
Marcus, Philip S.; Youssef, Ashraf
In early 1998 two of the three, long-lived anticyclonic, jovian white ovals merged. In 2000 the two remaining white ovals merged into one. Here we examine that behavior, as well as the dynamics of three earlier epochs: the Formation Epoch (1939-1941), during which a nearly axisymmetric band broke apart to form the vortices; the Kármán Vortex Stree…
XMM-Newton observations of four high-z quasars
Brinkmann, W.; Ferrero, E.
We present the results of XMM-Newton observations of four high-z quasars, two radio-loud and two radio-quiet. One of the radio-loud objects, PKS 2126-158, clearly shows absorption in excess of the galactic value as claimed before from ASCA and ROSAT observations. For PKS 2149-306 the evidence for excess absorption is only marginal in contrast to p…
On the formation of star clusters in the merger NGC 6240
Gallagher, J. S.; de Grijs, R.; Pasquali, A.
We identified star clusters in archived Hubble Space Telescope/Wide Field Planetary Camera 2 (HST/WFPC2) images of the merger and ultraluminous infrared galaxy NGC 6240, with the aim of investigating whether star cluster properties (luminosity, age and mass) in such an extreme environment differ from those of clusters in less luminous starburst ga…