Search Publications
Sigmoid CME source regions at the Sun: some recent results
Sterling, A. C.
Identifying coronal mass ejection (CME) precursors in the solar corona would be an important step in space weather forecasting, as well as a vital key to understanding the physics of CMEs. Twisted magnetic field structures are suspected of being the source of at least some CMEs. These features can appear sigmoid (S or inverse-S) shaped in soft X-r…
ISOPHOT observations of 3CR quasars and radio galaxies
de Graauw, T.; Barthel, P. D.; van Bemmel, I. M.
In order to check for consistency with the radio-loud AGN unification scheme, ISOPHOT data obtained for two small sets of intermediate redshift steep-spectrum 3CR radio galaxies and quasars are being examined. Supplementary submillimeter and centimeter radio data for the quasars are also taken into account, in order to assess the magnitude of any …
ISO Long Wavelength Spectrograph Observations of Cold Dust in Galaxies
Madore, Barry F.; Bianchi, Simone; Trewhella, Matthew +2 more
We describe observations of five nearby galaxies obtained using the Long Wavelength Spectrograph (LWS) on the Infrared Space Observatory (ISO). We observed five galaxies, using spectrograph apertures positioned at the galactic center and in the outskirts of the disk, to compare the spectral energy distribution of the emitting dust at different pos…
COMPTEL limits on 26Al 1.809 MeV line emission from gamma2 Velorum
Knödlseder, J.; Morris, D.; Schönfelder, V. +7 more
The Wolf-Rayet binary system
Statistics of quiet Sun extreme ultraviolet intensities
Solanki, S. K.; Schühle, U.; Landi, E. +2 more
The frequency distribution of the extreme ultraviolet (EUV) emission line intensities in the quiet Sun has in the past often been modelled using two Gaussians. This gives adequate fits to observed distributions of average statistical significance. In this paper we test this and other distribution functions against observed distributions with excep…
EUV Full-Sun Imaged Spectral Atlas Using the SOHO Coronal Diagnostic Spectrometer
Brekke, Pål; Thompson, William T.
The Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory (SOHO) carries out a regular program of measuring the full-disk irradiance using the Normal Incidence Spectrograph (NIS). The full-disk solar spectrum is returned in the wavelength bands 308-379 Å and 513-633 Å, with a spectral resolution between 0.3 and 0.6 Å.…
On the Transition Region Explosive Events
Tarbell, T. D.; Ryutova, M. P.
We describe the properties of high-velocity and explosive events in the solar transition region determined from time series of data taken by the Transition Region and Coronal Explorer and the SUMER instrument on the Solar and Heliospheric Observatory (SOHO) simultaneously in several chromospheric and transition region lines co-aligned with high-re…
The impact of resolution on observed Hii region properties from WFPC2 observations of M 101
Fricke, K. J.; Pleuss, P. O.; Heller, C. H.
Two continuum subtracted Hα HST frames of
The Morphology of the Solar Upper Atmosphere During the Sunspot Minimum
Wilhelm, K.; Dammasch, I. E.; Feldman, U.
The solar upper atmosphere (SUA) is defined as the volume above the photosphere occupied by plasmas with electron temperatures, T_e, above ~ 2×10^4 K. Until the Skylab era, only little was known about the morphology of the SUA, while the quality of the spectroscopic observations was continually improving. A spherically symmetric atmosphere was ass…
Time evolution of galactic warps in prolate haloes
Ideta, M.; Hozumi, S.; Tsuchiya, T. +1 more
A recent observation with the Hipparcos satellite and some numerical simulations imply that the interaction between an oblate halo and a disc is inappropriate for the persistence of galactic warps. Following on from this, we have compared the time evolution of galactic warps in a prolate halo with that in an oblate halo. The haloes were approximat…