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ISO. Monitoring the mass loss of a very late Helium flash star
Blommaert, J. A. D. L.; Asplund, M.; Kimeswenger, S. +3 more
We present ISOCAM observations of Sakurai's object (V4334 Sgr) covering the wavelength range of 4 to 15 mu m in seven filters. The photometry shows that in the period from February 1997 to February 1998 the flux over the whole wavelength range has increased by a factor of about ten. Combined with ground-based data we conclude that this increase is…
New Zr II oscillator strengths and the zirconium conflict in the HgMn star chi LUPI
Leckrone, D. S.; Sikström, C. M.; Lundberg, H. +4 more
Lifetimes on the sub-nanosecond scale for the levels v(2) D_{3/2}, v(2) F_{3/2} and v(2) F_{5/2} in the 4d5s5p configuration in Zr II have been measured, using the method of laser-induced fluorescence. Combined with branching fractions obtained with the Lund Ultraviolet (UV) Fourier Transform Spectrometer (FTS), experimental oscillator strengths h…
How Saturated Are Absorption Lines in the Broad Absorption Line Quasar PG 1411+442?
Matsuoka, M.; Brinkmann, W.; Wang, J. X. +1 more
Recently, convincing evidence was found for extremely large X-ray absorption by column densities greater than 1023 cm-2 in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. A detection …
The Evolution of the Galaxy Sizes in the New Technology Telescope Deep Field: A Comparison with Cold Dark Matter Models
Fontana, A.; Giallongo, E.; Menci, N. +2 more
The sizes of the field galaxies with I<=25 have been measured in the New Technology Telescope (NTT) Deep Field. Intrinsic sizes have been obtained after deconvolution of the point-spread function with a multi-Gaussian method. The reliability of the method has been tested using both simulated data and Hubble Space Telescope (HST) observations of…
Phase and Amplitude Difference between Velocity and Intensity Helioseismic Spectra
Kosovichev, A. G.; Nigam, R.
An explanation for the phase and amplitude difference between velocity and intensity oscillations of the Sun is provided. The phase difference along the modal lines in the power spectra was originally observed by Deubner and coworkers in 1989. From a simple adiabatic theory of solar oscillations, one expects this phase difference to be 90° for mod…
Center-to-limb variation of the solar oscillation. New results from MDI data
Schmidt, W.; Stix, M.; Wöhl, H.
{Using 17 hours of full-disk MDI Doppler data we have investigated the center-to-limb variation of the oscillatory wave spectrum of the solar photosphere. Power distributions in the k_hnu -plane are calculated for fields of 20(deg) x 20(deg) on the Sun, centered at every 10(deg) heliographic latitude. From the center-to-limb variation of the power…
Interplanetary scintillation measurements of the solar wind during Whole Sun Month: Comparisons with coronal and in situ observations
Thompson, B. J.; Biesecker, D. A.; Lazarus, A. J. +7 more
Two-site observations of interplanetary scintillation using the EISCAT facility can provide measurements of solar wind velocity at any point in the heliosphere between 15 and 120 solar radii (R). In this paper we discuss a series of observations made as part of the Whole Sun Month campaign (August 10 to September 8 1996) and compare the results wi…
The ``Papillon'' nebula: a compact H bt II blob in the LMC resolved by it HST
Heydari-Malayeri, M.; Charmandaris, V.; Zinnecker, H. +2 more
We present high spatial resolution HST imaging of the LMC compact {H ii} region N159-5. This high excitation blob is revealed to be a ``papillon'' or butterfly-shaped ionized nebula with the ``wings'' separated by { ~ },2''.3 (0.6 pc). Two subarcsecond features resembling a ``smoke ring'' and a ``globule'' are detected in the wings, the origin of …
Modulation of Cosmic Rays and Anomalous Components by CIRs
Potgieter, M. S.; Richardson, I. G.; Heber, B. +6 more
CIRs produce clearly visible recurrent modulation in the intensity of cosmic rays and anomalous components, but are not principally responsible for determining the overall global level of modulation. However, the localized variations imposed by CIRs in the parameters for propagation of energetic particles through the solar wind provide useful diag…
A Search for Microflaring Activity on DME Flare Stars. II. Observations of YZ Canis Minoris
Carpenter, K. G.; Robinson, R. D.; Percival, J. W.
We report on time-series photometric observations of the dM4.5e flare star YZ Canis Minoris obtained in 1993 November with the High Speed Photometer on board the Hubble Space Telescope. The data consist of five 30 minute time sequences with a sampling rate of 0.01 s that were taken through the F240W filter (centered at 240 nm with an 80 nm width).…