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Study of an extended EUV filament using SoHO/SUMER observations of the hydrogen Lyman lines
Heinzel, P.; Anzer, U.; Schmieder, B. +1 more
Context: .In previous work we determined the 3D structure of an EUV extension of the filament observed by SoHO/CDS on 15 October 1999. The determination of the 3D structure depends on the optical thickness τ912 at the hydrogen Lyman-continuum edge at 912 Å. The τ912 value was unknown, therefore it was taken as a free paramete…
Observations of concentrated generator regions in the nightside magnetosphere by Cluster/FAST conjunctions
André, M.; Hamrin, M.; Marghitu, O. +7 more
Here and in the companion paper, Marghitu et al. (2006), we investigate plausible auroral generator regions in the nightside auroral magnetosphere. In this article we use magnetically conjugate data from the Cluster and the FAST satellites during a 3.5-h long event from 19-20 September 2001. Cluster is in the Southern Hemisphere close to apogee, w…
Experimental investigation of auroral generator regions with conjugate Cluster and FAST data
Dandouras, I.; André, M.; Hamrin, M. +7 more
Here and in the companion paper, Hamrin et al. (2006), we present experimental evidence for the crossing of auroral generator regions, based on conjugate Cluster and FAST data. To our knowledge, this is the first investigation that concentrates on the evaluation of the power density, E·J, in auroral generator regions, by using in-situ measurements…
The faint 2005 hard state outburst of Aquila X-1 seen by INTEGRAL and RXTE
Rodriguez, J.; Corbel, S.; Shaw, S. E.
We report on the spectral analysis of RXTE and INTEGRAL data of the 2005 April outburst of the transient Atoll source Aql X-1. Although this outburst is one of the faintest ever detected for this source in the soft X-rays (RXTE/ASM), one of our INTEGRAL observations, taken close to the soft X-ray peak, shows that the source flux was quite high, wi…
Cluster observations of broadband electromagnetic waves in and around a reconnection region in the Earth's magnetotail current sheet
Walsh, A. P.; Freeman, M. P.; Petkaki, P.
We present an analysis of the electric and magnetic wave spectra on kinetic scales during several crossings of a reconnecting current sheet. The spectra were measured from 1 Hz or less up to 4096 Hz by the EFW, FGM and STAFF instruments onboard the Cluster spacecraft between 3 and 4 UT on 11 October 2001. During the event plasma flows of order of …
Coronal emission from the shocked circumstellar ring of SN 1987A
Lundqvist, P.; Spyromilio, J.; Gröningsson, P. +5 more
High resolution spectra with UVES/VLT of SN 1987A from December 2000 until November 2005 show a number of high ionization lines from gas with velocities of ± 350 km s-1, emerging from the shocked gas formed by the ejecta-ring collision. These include coronal lines from [Fe X], [Fe XI] and [Fe XIV] which have increased by a factor of 20 …
Propagation of interplanetary shocks through the solar wind and magnetosheath
Němeček, Z.; Šafránková, J.; Přech, L. +1 more
In order to estimate the propagation of interplanetary (IP) shocks in the solar wind and magnetosheath, we have analyzed a number of events for which simultaneous observations in the solar wind and magnetosheath were available. Among these events, those for which the arrival of the shock is observed by at least four spacecraft located in the solar…
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…