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The XMM-Newton/2dF survey - V. The radio properties of the X-ray population
Georgakakis, A.; Georgantopoulos, I.; Akylas, A. +3 more
In this paper, we cross-correlate the FIRST (Faint Images of the Radio Sky at Twenty centimeters) 1.4-GHz radio survey with a wide-field (1.6 deg2) shallow [fX(0.5 - 8keV) ~ 10-14erg s-1]XMM-Newton survey. We find 12 X-ray/radio matches representing 4 per cent of the X-ray-selected sample. Most of them a…
VISPO project: visible image-spectrometer for planetary observations
Piccioni, G.; Capaccioni, F.; De Petris, M. +3 more
Satellite instrumentations designed for planetary studies are often open to other interesting applications from ground: not only one can efficiently carry out detailed calibrations before space data become available, but also the prototypes of the satellite instruments can be successfully employed in different fields ranging from astrophysics to c…
Simulation studies of high-latitude magnetospheric boundary dynamics
Zhang, H.; Liu, Z. X.; Shi, Q. Q. +4 more
X-ray Archaeology of Galaxy Groups
Ponman, T. J.; Osmond, J. P. F.
We have assembled a sample of 60 galaxy groups in order to study the hot intragroup medium and better understand the processes by which it formed. We have analysed ROSAT data for all 60 groups and have obtained XMM data for a small subset. Here we present an initial analysis of the XMM data for NGC 5171, and a comparison with the ROSAT data. This …
A Search for Short-Timescale Microvariability in Active Galactic Nuclei in the Ultraviolet
Dolan, Joseph F.; Clark, L. Lee
We observed four active galactic nuclei (AGNs) (the type 1 Seyfert systems 3C 249.1, NGC 6814, and Mrk 205, and the BL Lac object 3C 371) using the High Speed Photometer on the Hubble Space Telescope (HST) to search for short-timescale microvariability in the UV. Continuous observations of ~3000 s duration were obtained for each system on several …
Probing diffusion parameters of suprathermal ions near heliospheric shocks
Klecker, B.; Hilchenbach, M.; Kallenbach, R. +1 more
The distribution functions of suprathermal ions in the energy range 35-2000 keV/amu associated with the interplanetary coronal mass ejection of 14-16 July 2000 are analyzed. The ion spectra agree with a theoretical model on momentum diffusion in two-dimensional magnetohydrodynamic turbulence.
Measurements and Calibration of Tropospheric Delay at Goldstone from the Cassini Media Calibration System
Tanner, A.; Keihm, S. J.; Rosenberger, H.
One and one-half years of near-continuous measurements of the troposphere-induced path delay at Goldstone have been analyzed in order to (1) characterize the troposphere-delay fluctuations in a statistical sense and (2) evaluate the path-delay calibration performance of the Media Calibration System (MCS) at DSS 25. Both the wet and dry components …
The Compton trail of gamma-ray bursts: A long-after glow
Parizot, E.; Allard, D.
As they travel through the gas of the host galaxy, some of the gamma-rays emitted in a Gamma-Ray Burst (GRB) may experience Compton scattering and reach an observer even if he is not located in the direction of the primary photon beam. Such a process will last until the GRB photons have left their host galaxy, and the ambient electron density beco…
Classical Cepheids and the Distances of HST Program Galaxies
Abrahamyan, H. V.
The distances of HST program galaxies are revised using the PL-relations we have obtained previously along with a different method from that employed by Freedman et al. On the average, the resulting distances to these galaxies have higher internal accuracies than those obtained before by others. In addition, we have used no corrections for metalli…
The Transition from Outburst to Low Level Activity in the Low-Mass X-Ray Binary SAX J1747.0-2853
Ubertini, P.; Bazzano, A.; Heise, J. +6 more
SAX J1747.0-2853 is an X-ray transient which exhibited several outbursts between 1998 and 2001 and most probably in 1976. The outburst of 2000 was the longest and brightest. We have analyzed X-ray data sets that focus on times around the 2000 outburst and were obtained with l BeppoSAX, XMM-Newton and l RXTE.