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Source standards for the radiometric calibration of astronomical telescopes in the VUV spectral range.

Huber, M. C. E.; Hollandt, J.; Kuehne, M. +1 more

On the basis of a high-current hollow-cathode discharge we have developed two transfer source standards suitable for the radiometric calibration of vacuum ultraviolet (VUV) telescopes. The source standards are transportable and (in their current design) produce a collimated beam of 5 and 10mm diameter. By irradiating the entrance aperture of the t…

Observations of Far-UV Emission From NGC 1275 With the Hopkins Ultraviolet Telescope

Ferguson, Henry C.; Davidsen, Arthur F.; Dixon, W. Van Dyke

The galaxy NGC 1275 was observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. NGC 1275 lies at the center of the Perseus cluster cooling flow and is surrounded by a bright emission-line nebula. The galaxy's far-UV spectrum shows a faint continuum and emission from Lyman α λ1216, C Iv λλ154…

ISOCAM 4µm imaging of the nuclear starburst in M 83.

Rouan, D.; Siebenmorgen, R.; Clavel, J. +6 more

We present ISOCAM images (1.5arcsec resolution), in the Brα line and in the continuum at 4µm, of the starburst nuclear region in the nearby galaxy M 83. The starburst is found to lie: a) along arc joining the 2µm sources at S and SW of the nucleus to the NW 10µm peak, a possible indication of a propagating star formation; b) at t…

IUE and Optical Observations of AM Herculis in Its Low State

Raymond, J. C.; Andronov, I. L.; Borisov, N. V. +3 more

Ten spectra of AM Herculis were obtained with the SWP instrument of the lUE over 2.5 orbital periods during a faint state in 1992 June. Significant periodic variability was seen in the UV flux and spectra. On the same day, UBVRI photometry was obtained at the 1.25 m optical telescope of the Crimean Astrophysical Observatory. A periodic brightening…

The Structure of the Stratospheric Aerosol Layer in the Equatorial and South Polar Regions of Jupiter

Moreno, Fernando

A one-dimensional code to study the microphysical processes affecting aerosol particles in the jovian stratosphere and upper troposphere has been developed. The algorithms are based on those developed by Turcoet al.(Turco, R. P., P. Hamill, O. B. Toon, R. C. Whitten, and C. S. Kiang 1979.J. Atmos. Sci.36, 699-717) and include the effects of partic…

The charge state of helium in the Jovian magnetosphere: a possible method to determine it

Krupp, N.; Keppler, E.

Ion measurements from the EPAC instrument on board the Ulysses spacecraft inside the Jovian dayside magnetosphere in February 1992 are reported. Energy/charge ( E/q) spectra for protons (0.5-1.0 MeV) and different ions (helium, oxygen and sulphur) in the energy range 0.4-9.0 MeV N ^-1 are concentrated on. In agreement with the earlier wo…

Discovery of a White Dwarf Companion (MS0354.6-3650 = EUVE J0356-366) to a G2V Star

Thorstensen, John R.; Vennes, Stephane; Christian, Damian J. +1 more

We present x-ray, ultraviolet, and optical observations of the mysterious EUV/soft x-ray source EUVE J0356-336 (= MS0354.6-3650). Initial Einstein observations identified this source with a cluster of galaxies, but the relatively high source count rate in the Extreme Ultraviolet Explorer (EUVE) 100 Å band and the lack of variability hinted that EU…

SWS H_2_ observations in the BD+40 4124 group.

Heras, A. M.; Prusti, T.; van den Ancker, M. E. +10 more

We report the detection of pure rotational lines of H_2_observed in the direction of three young stellar objects in the BD+40 4124 group, with the short-wavelength spectrometer (SWS) on board ISO. The rotational population distributions of all three stars are consistent with a thermal distribution. The derived kinetic temperatures are =~500K for B…

Interpretation of the Observed Plasma ``Turbulent'' Velocities as a Result of Magnetic Reconnection in Solar Flares

Antonucci, Ester; Benna, Carlo; Somov, Boris V.

One of the distinctive features of magnetic reconnection in current sheets, which has been proposed as the primary energy source in solar flares, is the presence of fast plasma outflows, or jets, whose velocities are nearly equal to the Alfvén speed and depend mainly on the electron and ion temperatures inside the current sheet. We briefly discuss…

Reply [to “Comment on ‘The underlying magnetic field direction in Ulysses observations of the southern polar heliosphere’ by Forsyth et al.”]

Balogh, A.; McComas, D. J.; Forsyth, R. J. +2 more