Search Publications

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.

Measuring the matter distribution within z = 0.2 cluster lenses with XMM-Newton

Smail, I.; Kneib, J. P.; Czoske, O. +4 more

We present an analysis of seven clusters observed by XMM-Newton as part of our survey of 17 most X-ray luminous clusters of galaxies at z ∼ 0.2 selected for a comprehensive and unbiased study of the mass distribution in massive clusters. Using the public software FTOOLS and XMMSAS we have set up an automated pipeline to reduce the EPIC MOS and pn …

Shell-like configuration in O+ ion velocity distribution at high altitudes in the dayside magnetosphere observed by Cluster/CIS

Lundin, R.; Nilsson, H.; Rème, H. +7 more

Available from http://www.copernicus.org/site/EGU/annales/22/7/2473.htm?FrameEngine=false;

Cluster: New Measurements of Plasma Structures in 3D

Escoubet, C. P.; Goldstein, M.; Laakso, H.

Reflection Model as Applied for the Analysis of Enhancements of Solar Cosmic Rays at Different Heliocentric Distances: An Example of the Event Observed in June 1991 onboard GRANAT and ULYSSES Spacecraft

Grigorenko, E. E.; Lyubimov, G. P.

In this paper we consider a large-scale enhancement of the intensity of solar protons (E = 1-20 MeV) observed in June 1991 for 26 days at different points of interplanetary space, onboard ULYSSES (in the time period under consideration it was located at a heliocentric distance of 3 AU, at an angular distance of ~70° to the East of the Sun-Earth li…