Search Publications
On the formation of the high-altitude stagnant cusp: Cluster observations
Davies, J. A.; Wild, J. A.; Fazakerley, A. N. +7 more
On 16 March 2002, Cluster moved from nightside to dayside, across the high-altitude northern cusp during an extended period of relatively steady positive IMF BY and BZ. Combined Cluster and SuperDARN data imply the existence of two reconnection sites: in the high-latitude northern hemisphere dusk and southern hemisphere dawn …
Near-Infrared, Kilosecond Variability of the Wisps and Jet in the Crab Pulsar Wind Nebula
Romani, R. W.; Eikenberry, S. S.; Rigaut, F. +6 more
We present a time-lapse sequence of 20 near-infrared (J and K' band) snapshots of the central 20×20 of the Crab pulsar wind nebula, taken at subarcsecond resolution with the Hokupa`a/QUIRC adaptive optics camera on the Gemini North Telescope and sampled at intervals of 10 minutes and 24 hr. It is observed that the equatorial wisps and polar knots …
Rights and wrongs of the Hipparcos data. A critical quality assessment of the Hipparcos catalogue
van Leeuwen, F.
A critical assessment of the quality of the Hipparcos data, partly supported by a completely new analysis of the raw data, is presented with the aim of clarifying reliability issues that have surfaced since the publication of the Hipparcos catalogue in 1997. A number of defects in the data are identified, such as scan-phase discontinuities and eff…
Cluster observations of currents in the plasma sheet during reconnection
Balogh, A.; Fazakerley, A. N.; Klecker, B. +6 more
We present Cluster PEACE observations of parallel electron currents near a reversal of accelerated ion flows which indicated that the spacecraft were in the vicinity of an active reconnection X-line (XL). Moments calculated from the PEACE electron spectrometer 3D 4s resolution data are analysed. We surveyed the electron current structure to reveal…
An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of the cluster Abell 2219
Smail, I.; Kneib, J. -P.; Altieri, B. +7 more
The massive cluster of galaxies Abell 2219 (z = 0.228) with two spectacular gravitational lensing arcs was observed at 14.3 µm (hereafter 15 µm) with the Infrared Space Observatory and results were published by Barvainis et al. (\cite{1999AJ....118..645B}). These observations have been reanalyzed using a method specifically designed fo…
Discovery of a bright X-ray transient in the Galactic Center with XMM-Newton
Burwitz, V.; Grosso, N.; Warwick, R. S. +4 more
We report the discovery of a bright X-ray transient object,
Discovery of a Solitary Dwarf Galaxy in the APPLES Survey
Pirzkal, Norbert; Walsh, Jeremy R.; Malhotra, Sangeeta +5 more
During the APPLES parallel campaign, the Hubble Space Telescope (HST) Advanced Camera for Surveys has resolved a distant stellar system, which appears to be an isolated dwarf galaxy. It is characterized by a circularly symmetric distribution of stars with an integrated magnitude mF775W=20.13+/-0.02, a central surface brightness µ<…
Kinematics of RHB stars to trace the structure of the Galaxy
de Boer, K. S.; Altmann, M.; Kaempf, T. A.
Red horizontal-branch (RHB) stars have been selected from the Hipparcos catalogue to investigate their kinematics and spatial distribution. Hipparcos parallaxes, literature radial velocities and Hipparcos proper motions, together with models for the gravitational potential of the Milky Way allow a calculation of the actual velocity vectors and the…
Kinematic and chemical evolution of early-type galaxies
Böhm, A.; Thomas, D.; Bender, R. +3 more
We investigate in detail 13 early-type field galaxies with 0.2<z<0.7 drawn from the Fors Deep Field. Since the majority (9 galaxies) is at z≈0.4, we compare the field galaxies to 22 members of three rich clusters with z=0.37 to explore possible variations caused by environmental effects. We exploit VLT/FORS spectra (R≈1200) and HST/ACS imagi…
The ionization structure of early-B supergiant winds
Massa, D.; Prinja, R. K.; Searle, S. C.
We present empirically determined ionization conditions for the winds of 106 luminous B0 to B5 stars observed by IUE. The UV wind lines are modelled to extract products of mass-loss rates times ionization fractions (\mdot qi(w) where w = v/v∞) for N V, C IV, Si IV, Si III, Al III and C II. We describe the general behaviour of…