Search Publications
A weak lensing analysis of a STIS dark-lens candidate
Schirmer, M.; Fosbury, R. A. E.; Schneider, P. +6 more
We perform a weak lensing analysis on a previously reported dark-lens candidate on STIS Parallel data \citep{meh02}. New VLT-data indicate that the reported signal originates from a small number of galaxies tangentially aligned towards the center of the STIS field but no signature for an extended mass distribution is found. We argue that we should…
Magnetic topology of coronal mass ejection events out of the ecliptic: Ulysses/HI-SCALE energetic particle observations
Sarris, E. T.; Malandraki, O. E.; Tsiropoula, G.
Solar energetic particle fluxes (Ee > 38 keV) observed by the ULYSSES/HI-SCALE experiment are utilized as diagnostic tracers of the large-scale structure and topology of the Interplanetary Magnetic Field (IMF) embedded within two well-identified Interplanetary Coronal Mass Ejections (ICMEs) detected at 56° and 62° south heliolatitudes by ULYSSE…
The INTEGRAL ground segment and its science operations centre
Parmar, A. N.; Schmidt, M.; Kuulkers, E. +10 more
The INTEGRAL ground segment is divided into operational and scientific components. The operational component consists of the Mission Operations Centre, the ground stations and communications lines while the scientific component comprises of a Science Operations Centre and Science Data Centre. The overall architecture of the ground segment is descr…
Wind-Ulysses in-situ thermal noise measurements of solar wind electron density and core temperature at solar maximum and minimum
Maksimovic, M.; Issautier, K.; Hoang, S. +2 more
The radio receivers on the Wind and Ulysses spacecraft in the solar wind continuously record spectra of the quasi-thermal plasma noise near the electron plasma frequency, from which the electron density and core temperature can be determined using the method of quasi-thermal noise spectroscopy. Such in-situ thermal noise measurements were obtained…
Plane-of-sky simulations of interplanetary shock waves
Dryer, M.; Smith, Z.; Fry, C. D. +3 more
We present simulated plane-of-sky maps of the shock waves in interplanetary space from several representative solar events by using the Hakamada-Akasofu-Fry solar wind model (HAFv.2). This kinematic model uses a three-dimensional approach to construct plane-of-sky maps of interplanetary shock waves initiated by solar flares and CMEs. The simulated…
Giant Meterwave Radio Telescope observations of an M2.8 flare: Insights into the initiation of a flare-coronal mass ejection event
Janardhan, P.; Kundu, M. R.; White, S. M. +3 more
We present the first observations of a solar flare with the GMRT. An M2.8 flare observed at 1060 MHz with the GMRT on 17 November 2001 was associated with a prominence eruption observed at 17 GHz by the Nobeyama radioheliograph and the initiation of a fast partial halo CME observed with the LASCO C2 coronagraph. Towards the start of the eruption, …
Formation of bulges in very late-type galaxies from super star clusters
Deng, Z. G.; Fu, Y. N.; Huang, J. H.
The dynamical evolution of super star clusters (SSCs) moving in the background of a dark matter halo has been investigated as a possible event responsible for the formation of bulges in late-type spirals. The underlying physical processes include sinking of SSCs due to the dynamical friction and stripping of SSCs on their way to the centre. Our mo…
IBIS Veto System. Background rejection, instrument dead time and zoning performance
Bird, A. J.; Ubertini, P.; Bazzano, A. +7 more
IBIS is the high energy imager on board the INTEGRAL satellite. The gamma-ray instruments on board will take advantage of the long uninterrupted observation made possible by the very eccentric orbit (10 000 km perigee and 152 000 km apogee). A disadvantage for orbits outside the protection of the van Allen belts is the exposure to cosmic and solar…
An XMM-Newton observation of the narrow-line Seyfert 1 galaxy Markarian 896
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
We present XMM-Newton observations of the narrow-line Seyfert 1 galaxy Markarian 896. Over the 2-10 keV band, an iron emission line, close to 6.4 keV, is seen. The line is just resolved and has an equivalent width of ~170 eV. The broad-band spectrum is well modelled by a power-law slope of Γ~ 2.03, together with two blackbody components to fit the…
Visual orbit for the low-mass binary Gliese 22 AC from speckle interferometry
Leinert, Ch.; Docobo, J. A.; Woitas, J. +1 more
Based on 14 data points obtained with near-infrared speckle interferometry and covering an almost entire revolution, we present a first visual orbit for the low-mass binary system Gliese 22 AC. The quality of the orbit is largely improved with respect to previous astrometric solutions. The dynamical system mass is 0.592+/- 0.065 Msun, w…