Search Publications
Origin, Injection, and Acceleration of CIR Particles: Theory Report of Working Group 7
Simnett, G. M.; Mann, G.; Keppler, E. +10 more
On the basis of the observational picture established in the report of Mason, von Steiger et al. (1999) the status of theoretical models on origin, injection, and acceleration of particles associated with Corotating Interaction Regions (CIRs) is reviewed. This includes diffusive or first-order Fermi acceleration at oblique shocks, adiabatic decele…
Abundances of metal-weak thick-disc candidates
Bonifacio, P.; Molaro, P.; Centurion, M.
High-resolution spectra of five candidate metal-weak thick-disc stars suggested by Beers & Sommer-Larsen are analysed to determine their chemical abundances. The low abundance of all the objects has been confirmed, with metallicity reaching [Fe/H]=-2.9. However, for three objects the astrometric data from the Hipparcos catalogue suggest they a…
The Low-redshift Intergalactic Medium
Shull, J. Michael; Stocke, John T.; Penton, Steven V.
The low-redshift Lyα forest of absorption lines provides a probe of large-scale baryonic structures in the intergalactic medium, some of which may be remnants of physical conditions set up during the epoch of galaxy formation. We discuss our recent Hubble Space Telescope (HST) observations and interpretation of low-z Lyα clouds toward nearby Seyfe…
Synoptic Sun during the first Whole Sun Month Campaign: August 10 to September 8, 1996
Thompson, B. J.; Hoeksema, J. T.; Biesecker, D. A. +6 more
A large number of synoptic maps from a variety of instruments are used to show the general morphology of the Sun at the time of the First Whole Sun Month Campaign. The campaign was conducted from August 10 to September 8, 1996. The synoptic maps cover the period from Carrington rotation 1912/253° to Carrington rotation 1913/45°. The synoptic maps …
In-ecliptic CIR-associated energetic particle events and polar coronal hole structures: SOHO/COSTEP observations for the Whole Sun Month Campaign
Heber, Bernd; Szabo, Adam; Bothmer, Volker +7 more
The Solar and Heliospheric Observatory (SOHO), in halo orbit around the L1 Lagrangian point of the Sun-Earth system, combines a unique set of instruments for studies of the Sun and the heliosphere. SOHO's Comprehensive Suprathermal and Energetic Particle Analyser measures in situ particles in the energy range 44 keV/particle to above 53 MeV/nucleo…
Damping and frequency reduction of the f-mode due to turbulent motion in the solar convection zone
Murawski, K.; Mȩdrek, M.; Roberts, B.
Solar f-mode properties were observed recently with high accuracy using high-resolution Michelson Doppler Imager (MDI) data from SOHO (Duvall et al. 1998). According to these observations, linewidths increase with wavenumber k and the f-mode frequency omega is significantly lower than the frequency omega_0 given by the simple dispersion relation o…
Starburst nuclei: ISO observations and models
Siebenmorgen, R.; Krügel, E.; Zota, V.
1.) We present photometric data of three starburst galaxies (Mkn 496, Mkn 1116, NGC 6000) obtained with the Infrared Space Observatory (ISO) in the wavelength bands 2.5-11.6 mu m (P-40) and 120-200 mu m (P-22). In all galaxies, we detect the 9.7 mu m silicate absorption feature and strong emission from PAHs; only the 3.3 mu m band is below the sen…
Abundances of the Elements in Sharp-lined Early-Type Stars from IUE High-Dispersion Spectrograms. II. The Nitrogen Deficiency in Mercury-Manganese Stars
Adelman, Saul J.; Leckrone, David S.; Roby, Scott W.
We determine nitrogen abundances from co-added IUE high-dispersion SWP spectrograms of four HgMn stars and five normal or superficially normal main-sequence B and A stars. We find N deficiencies in the HgMn stars greater than previously reported (depletion factors of 135-400 relative to the Sun). N abundance discrepancies from UV and IR studies of…
Filament channel structures in a SI IV line related to a 3d magnetic model
Vial, J. -C.; Aulanier, G.; Schmieder, B. +2 more
A recent 3D magnetic model of filament support (Aulanier and Démoulin, 1998) has shown that specific morphologies derived from the model, based on SOHO/MDI magnetograms, match quite well with the observations of a filament observed in Hα and Ca ii lines with the German telescope VTT in Tenerife on 25 September 1996 (Aulanier et al., 1998, 1999a). …
RXTE, ROSAT, EUVE, IUE, and Optical Observations through the 45 Day Supercycle of V1159 Orionis
Walker, Gary; Szkody, Paula; Hoard, D. W. +10 more
A complete 45 day supercycle of the cataclysmic variable V1159 Ori comprising a superoutburst and eight normal outbursts was observed. Coverage included ground-based optical observations as well as observations with RXTE for 38 days, ROSAT for 34 days, IUE for 27 days, and Extreme Ultraviolet Explorer (EUVE) for 10 days. The resulting light curves…