Search Publications
Dependence of UV radiance of the quiet Sun on the solar cycle: Surface magnetic fields as the cause
Solanki, S. K.; Pauluhn, A.
The quiet-Sun UV radiance depends on the solar cycle, as shown by data collected by the SUMER spectrograph on the Solar and Heliospheric Observatory (SOHO). The cause of this dependence is still unclear. Here the hypothesis is tested for the He I 584 Å line that these variations are due to changes in the magnetic network. The quiet-Sun variability…
On the nature of extended EUV filaments
Heinzel, P.; Anzer, U.
This paper describes the properties of extended EUV filaments and the theoretical modelling of them. We summarise the general aspects of the depression of EUV-line emission and give an interpretation of recent filament observations in transition-region and coronal lines. The EUV filament was found to be located relatively high in the corona (at le…
ISOCAM-CVF imaging of M 16
Pilbratt, G. L.; White, Glenn J.; Urquhart, J. S. +1 more
We present ISOCAM observations (5-17 mu m) of the HST M 16 field, including the striking elephant trunk structures. The spectroscopic data have been obtained using the ISOCAM-CVF low-resolution mode, having a spectral resolution of ~ 40 (lambda /Delta lambda ) and a pixel size of 6''. The spectra show a combination of Unidentified Infra…
Effect of anisotropic velocity distribution on the linear polarization of coronal lines. Does the ion cyclotron exist in the inner corona?
Solanki, S. K.; Raouafi, N. -E.
The effect of an anisotropic velocity field distribution of scattering ions on the polarization parameters of a spectral line emitted by resonance scattering is considered. The anisotropy of the velocity field distribution can be interpreted in terms of the ion-cyclotron effect that is believed to influence some heavy ions in the solar corona. We …
Models for the positive latitude e{-}e{+} annihilation feature
Knödlseder, J.; Guessoum, N.; Jean, P. +1 more
Galactic maps of e-e+ annihilation radiation based on CGRO-OSSE, SMM and TGRS data have indicated the existence of an extended component at positive Galactic latitudes (l~ -2 deg, b~ 7 deg), in addition to the emission from the galactic bulge and disk (Purcell et al. \cite{Purcell97}; Cheng et al. \cite{…
GRB 021219: The first Gamma-Ray Burst localized in real time with IBAS
Götz, D.; Mereghetti, S.; von Kienlin, A. +5 more
On December 19, 2002, during the Performance and Verification Phase of INTEGRAL, a Gamma-Ray Burst (GRB) has been detected and localized in real time with the INTEGRAL Burst Alert System (IBAS). Here we present the results obtained with the IBIS and SPI instruments. The burst had a time profile with a single peak lasting about 6 s. The peak spectr…
The Input Catalogue for the OMC camera onboard INTEGRAL
Mas-Hesse, J. M.; Jordi, C.; Figueras, F. +6 more
The Optical Monitoring Camera (OMC) onboard INTEGRAL (launched on October 17, 2002) has been designed to obtain V-Johnson photometry simultaneously with high energy observations at X-ray (3-35 keV) and gamma-ray (15 keV-10 MeV) performed by the main instruments onboard INTEGRAL. Due to technical limitations on the data processing electronics and t…
2D MHD modelling of compressible and heated coronal loops obtained via nonlinear separation of variables and compared to TRACE and SoHO observations
Gontikakis, C.; Tsinganos, K.; Aschwanden, M. J. +2 more
An analytical MHD model of coronal loops with compressible flows and including heating is compared to observational data. The model is constructed via a systematic nonlinear separation of the variables method used to calculate several classes of exact MHD equilibria in Cartesian geometry and uniform gravity. By choosing a particularly versatile so…
Variability of The Old Nova V603 Aquilae in UV and X-ray bands
Szkody, P.; Schwarzenberg-Czerny, A.; Borczyk, W.
We present the results of a campaign of simultaneous observations of V603 Aql in the X-ray and UV bands accomplished with the IUE and ROSAT satellites. Simultaneous observations cover 20 orbital cycles, while the total span of all the observations is 40 cycles. This constitutes the longest continuous UV time series of simultaneous space observatio…
The microwave subsecond pulse of September 17, 2001: The spectrum, location and size of the source
Yan, Yihua; Altyntsev, A. T.; Meshalkina, N. S. +2 more
We examine simultaneous observations of microwave subsecond pulses with high temporal, spatial and spectral resolution from the Siberian Solar Radio Telescope (5.7 GHz, 14 ms resolution) and from the spectropolarimeters (5.2-7.6 GHz, 6 ms) of the National Astronomical Observatories. The September 17, 2001 flare is discussed in detail. The subsecon…