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Observations of the Hubble Deep Field with the Infrared Space Observatory - V. Spectral energy distributions, starburst models and star formation history
Elbaz, D.; Danese, L.; Franceschini, A. +16 more
We have modelled the spectral energy distributions of the 13 Hubble Deep Field (HDF) galaxies reliably detected by the Infrared Space Observatory (ISO). For two galaxies the emission detected by ISO is consistent with being starlight or the infrared `cirrus' in the galaxies. For the remaining 11 galaxies there is a clear mid-infrared excess, which…
The Cluster Ion Spectrometry (cis) Experiment
Lundin, R.; Balsiger, H.; Klecker, B. +43 more
A Powerful Nuclear Starburst in the Seyfert Galaxy Markarian 477: Implications for the Starburst-Active Galactic Nucleus Connection
Leitherer, C.; Wilson, A. S.; Heckman, T. M. +5 more
There have been many suggestions that starbursts may play an important role in Seyfert galaxies. Recent analyses of the UV, optical, and near-IR ``featureless continuum'' (FC) in type 2 Seyfert nuclei have provided indirect evidence that the FC may be produced by a compact starburst and that this starburst may provide a power source for the pronou…
Evidence of an Erupting Magnetic Flux Rope: LASCO Coronal Mass Ejection of 1997 April 13
St. Cyr, O. C.; Paswaters, S. E.; Simnett, G. M. +7 more
A coronal mass ejection (CME) observed by LASCO exhibits evidence that its magnetic field geometry is that of a flux rope. The dynamical properties throughout the fields of view of C2 and C3 telescopes are examined. The results are compared with theoretical predictions based on a model of solar flux ropes. It is shown that the LASCO observations a…
Younger and Brighter - New Distances to Globular Clusters Based on HIPPARCOS Parallax Measurements of Local Subdwarfs
Reid, I. Neill
We have used new parallax measurements, obtained by the Hipparcos satellite, of fifteen nearby, metal-poor stars to re-define the subdwarf main-sequence. All of these stars have parallaxes determined to an accuracy of at least 12%. Comparing these measurements against previous ground-based data for nine stars reveals a systematic offset of 5%, in …
First Results from VIRGO, the Experiment for Helioseismology and Solar Irradiance Monitoring on SOHO
Gough, Douglas; Domingo, Vicente; Appourchaux, Thierry +19 more
First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observations started mid-January 1996 for the radiometers and sunphotometers and near the end of March for the luminosity oscillation imager. The performance of all t…
Line-blanketed model atmospheres for R Coronae Borealis stars and hydrogen-deficient carbon stars.
Eriksson, K.; Gustafsson, B.; Asplund, M. +1 more
We have constructed line-blanketed model atmospheres for the hydrogen-deficient and carbon-rich R Coronae Borealis (RCrB) stars, as well as for the similar hydrogen-deficient carbon (HdC) stars and the cool extreme helium (EHe) stars. Improved continuum opacities have been used together with realistic line absorption data for atomic and molecular …
First Results of the SUMER Telescope and Spectrometer on SOHO - II. Imagery and Data Management
Grewing, M.; Wilhelm, K.; Marsch, E. +13 more
SUMER - Solar Ultraviolet Measurements of Emitted Radiation - is not only an extreme ultraviolet (EUV) spectrometer capable of obtaining detailed spectra in the range from 500 to 1610 Å, but, using the telescope mechanisms, it also provides monochromatic images over the full solar disk and beyond, into the corona, with high spatial resolution. We …
Synthetic Spectra of Hydrodynamic Models of Type Ia Supernovae
Baron, E.; Branch, David; Hauschildt, Peter H. +2 more
We present detailed non-LTE synthetic spectra of hydrodynamic supernovae (SNe) Ia models. We make no assumptions about the form of the spectrum at the inner boundary. We calculate both Chandrasekhar-mass deflagration models and sub-Chandrasekhar ``helium detonators.'' Gamma-ray deposition is handled in a simple, accurate manner. We have parameteri…
HIPPARCOS data on Herbig Ae/Be stars: an evolutionary scenario.
Waters, L. B. F. M.; Catala, C.; The, P. S. +4 more
Fundamental astrophysical parameters (distance, temperature, luminosity, mass, age) of a sample of 10 Herbig Ae/Be candidates and 3 non-emission line A and B stars in star forming regions were computed combining Hipparcos parallaxes with data from literature. All genuine Herbig stars in our sample are located between the birthline and the zero-age…