Search Publications
Spatial gradients in the plasmasphere from Cluster
Dunlop, M. W.; Décréau, P. M. E.; De Keyser, J. +2 more
The Cluster mission allows the study of the plasmasphere with four-point measurements, including its overall density distribution, plasmaspheric plumes close to the plasmapause, and density irregularities inside the plasmasphere. The purpose of this letter is to examine the geometry and orientation of the overall density structure and of the magne…
On the reliability of CIVλ1549 as an abundance indicator for high-redshift star-forming galaxies
Pettini, Max; Steidel, Charles C.; Crowther, Paul A. +1 more
We reconsider the use of the equivalent width of CIVλ1549, EW(CIV), as an indicator of the oxygen abundance in star-forming galaxies, as proposed by Heckman et al. for nearby starbursts. We refine the local calibration of EW(CIV) versus log(O/H) by using a restricted wavelength window which minimizes blending with interstellar absorption lines. Wh…
Interplanetary Lyman α line profiles: variations with solar activity cycle
Schmidt, W.; Bertaux, J. -L.; Lallement, R. +4 more
Aims.Interplanetary Lyman α line profiles are derived from the SWAN H cell data measurements. The measurements cover a 6-year period from solar minimum (1996) to after the solar maximum of 2001. This allows us to study the variations of the line profiles with solar activity.
Methods: .These line profiles were used to derive line shifts and lin…
CLUSTER spacecraft observation of a thin current sheet at the Earth’s magnetopause
Fränz, M.; Dandouras, I.; Khotyaintsev, Y. +7 more
On March 30, 2002 within 17 min the four CLUSTER spacecraft crossed the Earth’s high-latitude magnetopause three times. We found that all three magnetopause current sheets are nearly co-planar on the scales of the CLUSTER spacecraft separation. The thickness of the current sheets changes from 1 to 40 magnetosheath-proton thermal gyro-radii. The th…
Coronal Magnetic Field Topology over Filament Channels: Implication for Coronal Mass Ejection Initiations
Luhmann, Janet; Li, Yan
The magnetic field topology at the coronal mass ejection (CME) source regions has been one of the major focuses of CME initiation models. While the ``breakout'' model requires a quadrupolar magnetic topology in the solar corona to enable an eruption, other models have shown that a bipolar magnetic topology can be the source region of a CME. In thi…
Bifurcated current sheets: Statistics from Cluster magnetometer measurements
Balogh, A.; Kistler, L. M.; El-Alaoui, M. +3 more
We report on a statistical study of bifurcated current sheets in the near-Earth plasma sheet and the association of such current sheets with a near-Earth neutral line. Support for this interpretation is provided by a global MHD simulation generated for geomagnetic and solar wind conditions prevailing at the time when a bifurcated current sheet was…
Rosetta Lander—Philae: Implications of an alternative mission
Rosenbauer, H.; Hilchenbach, M.; Ulamec, S. +5 more
“Rosetta” is a Cornerstone Mission of the Horizon 2000 ESA Programme. Its goal is to rendezvous with a comet and to study its nucleus and coma using an orbiting spacecraft and a landed platform. The latter is called Philae; the Rosetta Lander has been designed to land softly on the comet nucleus and is equipped with 10 scientific instruments to pe…
On the profile of intense high-altitude auroral electric fields at magnetospheric boundaries
Nilsson, H.; Karlsson, T.; Marchaudon, A. +5 more
The profile of intense high-altitude electric fields on auroral field lines has been studied using Cluster data. A total of 41 events with mapped electric field magnitudes in the range between 0.5-1 V/m were examined, 27 of which were co-located with a plasma boundary, defined by gradients in particle flux, plasma density and plasma temperature. M…
XMM-Newton Detection of X-Ray Emission from the Compact Steep-Spectrum Radio Galaxy 3C 303.1
O'Dea, Christopher P.; Baum, Stefi; Worrall, D. M. +3 more
Using XMM-Newton we detect faint unresolved X-ray emission from the compact steep-spectrum radio galaxy 3C 303.1. We detect a thermal component at kT~=0.8 keV, which seems likely to be produced in the interstellar medium (ISM) of the host galaxy. There is evidence for a second component in the spectrum whose nature is currently ambiguous. Plausibl…
A Genuine Intermediate-Age Globular Cluster in M33
Chandar, Rupali; Sarajedini, Ata; Goudfrooij, Paul +1 more
We present deep integrated-light spectroscopy of nine M33 globular clusters taken with the Hectospec instrument at the MMT Observatory. Based on our spectroscopy and previous deep color-magnitude diagrams obtained with HST WFPC2, we present evidence for the presence of a genuine intermediate-age globular cluster in M33. The analysis of Lick line i…