Search Publications

Calibration of TRACE Lyman-α images using SOHO/SUMER observations

Kim, Sungsoo S.; Roh, Hee-Seon; Cho, Kyung-Seok +1 more

1216 Å channel images from the Transition Region and Coronal Explorer (TRACE) contain not only the desired HI Lyman-α (Lα) line emission from the Sun, but also some UV continuum around 1600 Å. By comparing TRACE data with Lα images from the Very High Angular Resolution Ultraviolet Telescope, Handy et al. proposed a simple procedure to remove the c…

On the interstellar extinction law toward young stars

Lamzin, S. A.

We have determined the atomic hydrogen column density N HI toward all of the young stars from the Taurus-Auriga-Perseus star-forming complex for which the corresponding spectra are available in the Hubble Space Telescope archive (nine stars) by analyzing the Lyα line profile. We show that the stars studied, except DR Tau, lie not far from the edge…

High resolution spectroscopy of giant HII regions around young massive clusters

Maiolino, R.; Vanzi, L.; Scatarzi, A. +1 more

We present new high-resolution optical spectroscopy of giant HII regions around three young

massive clusters located in the blue dwarf galaxies NGC 5253 and He 2-10.

We used the observations to derive the mass of the clusters under the hypothesis of virialization. The virial masses exceed the optical ones. In one case, however, the viria…

Distribution of positron annihilation radiation

Milne, Peter A.

The SPI instrument on-board the ESA/INTEGRAL satellite is engaged in a mission-long study of positron annihilation radiation from the Galaxy. Early results suggest that the disk component is only weakly detected at 511 keV by SPI. We review CGRO/OSSE, TGRS and SMM studies of 511 keV line and positronium continuum emission from the Galaxy in light …

Light bending models in AGNs

Miniutti, G.

We review the MCG-6-30-15 observations and results that provided the motivation for the light bending model. We present a summary of the main properties of the model and discuss its application to MCG-6-30-15 briefly mentioning other X-ray sources showing the same qualitative behaviour. Finally, we report on one of the most spectacular cases so fa…

Coupling effects throughout the solar atmosphere: 2. Model of energetically open circuit

Ryutova, M.

EUV structures in the solar atmosphere are studied on the basis of the energetically open equivalent circuits. The systems consist of current carrying magnetic loops that interconnect a high β energy-production region with a low β dissipation region and include the transition region where the most efficient generation of currents and transport of …

Calibration of the PRONAOS/SPM submillimeter photometer

Bernard, J. -P.; Dupac, X.; Giard, M. +12 more

Context: .
Aims: .PRONAOS is a stratospheric balloon-borne project dedicated to submillimeter astronomy. Sensitive to low emission gradients, PRONAOS allowed pointed observations in four photometric bands between 200 µm and 1.2 mm with an angular resolution of 2' to 3.5'. We present here the PRONAOS calibration strategy and the accuracy …

Multidimensional physicochemical models of the near-nucleus coma: Present achievements and requested future developments

Crifo, J. -F.

The published multidimensional physicochemical simulations of the near-nucleus coma (hereafter "NNC") are reviewed. The goals of these simulations are to understand the physical origin of the observed NNC structure(s), and to relate the latter to properties of the nucleus - an inference which is often done on the basis of subjective impressions on…

Multi-aperture photometry of extended IR sources with ISOPHOT. I. The nature of extended IR emission of planetary Nebulae

Walker, H. J.; Richards, P. J.; Müller, T. G. +2 more

Context: .ISOPHOT multi-aperture photometry is an efficient method to resolve compact sources or to detect extended emission down to relatively faint levels with single detectors in the wavelength range 3 to 100 µm.
Aims: .Using ISOPHOT multi-aperture photometry and complementary ISO spectra and IR spectral energy distributions we discus…

On Deriving Plasma Velocity Information from CDS/NIS Observations: Application to the Dynamics of Blinkers

Brooks, David Hamilton; Bewsher, Danielle

Using standard instrument software and two independently developed data reduction and analysis procedures, we re-examine the accuracy of plasma velocity information derived from data obtained by the Solar and Heliospheric Observatory (SOHO)-Coronal Diagnostic Spectrometer (CDS). We discuss only the Ov 629 Å line data obtained by the Normal Inciden…