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Detecting sub-glacial aquifers in the north polar layered deposits with Mars Express/MARSIS
Gurnett, D. A.; Farrell, W. M.; Plaut, J. J. +1 more
The penetration of the MARSIS radar signal into the polar ice mass is modeled to determine the capability of the instrument to locate sub-glacial aquifers. As a ground penetrating radar, the orbiting MARSIS transmits a signal >1 W between 1-5 MHz. In this work we will investigate the effect of ice reflective and conductive losses on the radar-d…
On the Nature of the Unidentified X-ray/γ-ray Sources Igr J18027–1455 and Igr J21247+5058
Mirabel, I. F.; Combi, J. A.; Ribó, M.
We present a multiwavelength study of the environment of the unidentified X-ray/γ-ray sources IGR J18027–1455 and IGR J21247 + 5058, recently discovered by the IBIS/ISGRI instrument, onboard the INTEGRAL satellite. The main properties of the sources found inside their position error circles, give us clues about the nature of these high-energy sour…
Rapid X-Ray Variability of Seyfert 1 Galaxies
Iwasawa, K.; Vaughan, S.; Fabian, A. C.
The rapid and seemingly random fluctuations in X-ray luminosity of Seyfert galaxies provided early support for the standard model in which Seyferts are powered by a supermassive black hole fed from an accretion disc. However, since EXOSAT there has been little opportunity to advance our understanding of the most rapid X-ray variability. Observatio…
Photon scattering in the solar ultraviolet lines of HeI and HeII
Jordan, C.; Houdebine, E. R.; Smith, G. R.
Observations made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO) are used to investigate the behaviour of the intensities of the emission lines of HeI, HeII and OIII at the quiet Sun-centre and at θ= 60° towards the equatorial limb. The aim is to examine the possible effects of photon scatterin…
Solar wind velocity measurements near the sun using Ulysses radio amplitude correlations at two frequencies
Plettemeier, D.; Bird, M. K.; Efimov, A. I. +4 more
Measurements of solar wind velocity have been derived from simultaneous coronal sounding observations of radio amplitude scintillations at both S-band and X-band during the solar conjunction of the Ulysses spacecraft in August 1991. The signal amplitude was recorded with an averaging time of 1 s. A cross-correlation analysis between S- and X-band …
Double Star, Cluster, and ground-based observations of magnetic reconnection during an interval of duskward oriented IMF: preliminary results
Balogh, A.; Davies, J. A.; Wild, J. A. +3 more
We present a space- and ground-based study exploiting data from the coordinated Cluster and Double Star missions in order to investigate dayside magnetic reconnection under BY+ dominated IMF conditions. In-situ observations of magnetosheath flux transfer events combined with measurements of pulsed poleward and dawnward directed flows in…
Catalog of Galaxy Morphology in Four Rich Clusters: Luminosity Evolution of Disk Galaxies at 0.33 < z < 0.83
Saintonge, Amélie; Yee, H. K. C.; Carlberg, R. G. +2 more
Hubble Space Telescope (HST) imaging of four rich, X-ray-luminous, galaxy clusters (0.33<z<0.83) is used to produce quantitative morphological measurements for galaxies in their fields. Catalogs of these measurements are presented for 1642 galaxies brighter than F814W(AB)=23.0. Galaxy luminosity profiles are fitted with three models: exponen…
Observations of the companion to the pulsar PSR B1718-19. The role of tidal circularisation
van Kerkwijk, M. H.; Janssen, T.
We present optical and infrared observations taken with the Very Large Telescope of the eclipsing binary pulsar system
The Earth's Magnetopause: Reconstruction of Motion and Structure
de Keyser, Johan
The Earth’s magnetosphere is an accessible region for improving our knowledge of the dynamics of collisionless plasmas. We focus here on the magnetopause a typical plasma discontinuity. We discuss recent developments in describing the structure of the magnetopause by means of reconstruction techniques, which translate in situ data into spatial inf…
The Magnetospheric cusps: A Summary
Zong, Q. G.; Fritz, T. A.
The polar cusps of the magnetosphere are key regions for the transfer of mass, momentum, and energy from the solar wind into the magnetosphere. Understaning these key regions and the dynamical interactions that occur there are fundamentally important to determining the physical nature of the magnetosphere. In this paper we try to summarize many of…