Search Publications
The widths of the unidentified infrared bands (UIBs). Molecular or solid-state carriers?
Papoular, Renaud
The molecular and solid-state models of the UIB widths are confronted with observations from ground-based telescopes and the ISO satellite. The PAH (Polycyclic Aromatic Hydrocarbons) model requires that free-flying molecules be excited by vacuum UV radiation. However, recent laboratory measurements of vibrational emission reveal that, in this case…
Ultraviolet spectral properties of magellanic and non-magellanic irregulars, H BT II and starburst galaxies
Alloin, D.; Pastoriza, M. G.; Bonatto, C. +1 more
This paper presents the results of a stellar population analysis performed on nearby (V_R<=5 000 km s^{-1}) star-forming galaxies, comprising magellanic and non-magellanic irregulars, H Ii and starburst galaxies observed with the IUE satellite. Before any comparison of galaxy spectra, we have formed subsets according to absolute magnitude and m…
IRAS 03313+6058: an AGB star with 30 micron emission
Szczerba, R.; Jiang, B. W.; Deguchi, S.
This paper reports a detection of the 30 micron emission feature from the C-rich Asymptotic Giant Branch (AGB) star IRAS 03313+6058 based on the ISO-SWS observation. Modeling of the spectral energy distribution shows that this emission starts at about 20 micron and possibly extends to the limit (45 micron) of the observation. By assuming MgS as th…
ORFEUS II echelle spectra: deuterium and molecular hydrogen in the ISM towards BD +39 3226
de Boer, K. S.; Heber, U.; Marggraf, O. +2 more
In ORFEUS II spectra of the sdO star
Dust extinction and intrinsic SEDs of carbon-rich stars. II. The hot carbon stars
Bergeat, J.; Knapik, A.; Rutily, B.
The present work is an extension of a recent study by Knapik & Bergeat (\cite{knapik}, henceforth called Paper I) of the spectral energy distributions (SEDs) of about 300 cool carbon-rich variables and of the interstellar extinction observed on their line of sights. The methods were originally developed for Semi-Regular (SR) and Irregular (L)-…
A complex Lyman limit system at z=1.9 towards HS 1103+6416
Reimers, D.; Hagen, H. -J.; Burles, S. +3 more
We analyse absorption lines in optical and ultraviolet spectra of the bright (V=15.8, z=2.19) QSO HS 1103+6416. High-resolution (FWHM =8 km s(-1) ) optical spectra have been obtained with the Keck 10 m telescope in the range from 3180 to 5780 Angstroms. Ultraviolet observations in the range from 1150 to 3280 Angstroms were performed with the FOS a…
ROSAT X-ray observations of the interacting pair of galaxies NGC 4410: evidence for a central starburst
Hensler, G.; Tschöke, D.; Junkes, N.
We present X-ray observations of the interacting pair of galaxies NGC 4410a/b with the ROSAT HRI and PSPC. The ROSAT HRI images reveal a point-like source corresponding to NGC 4410a and an X-ray halo, extending 10'' from the nucleus toward the southeast. The halo emission accounts for ~ 1/3 (LX = 1.3\tento{41} erg s(-1) in the 0.1-2.4 k…
Temporal variability in the electron density at the solar transition region
Doyle, J. G.; Keenan, F. P.; O'Shea, E. +1 more
The electron density as measured in the transition region of a coronal hole, a `quiet' Sun region at disk center plus an active region shows variations of up to a factor of two at T_e ~ 1.5 105 K, lasting at most only a few minutes. There is remarkable agreement between the number of such variations, their temporal variability and durat…
Hubble Deep Field guide star photometry
Zwintz, K.; Kuschnig, R.; Weiss, W. W. +2 more
Since the advent of asteroseismology as a promising innovative tool for investigating internal stellar structure, numerous attempts to detect solar type oscillations in distant stars have been conducted. The three Fine Guidance Sensors of the Hubble Space Telescope can contribute to asteroseismology, but only after the data have been corrected for…
The eclipse of the symbiotic star SY MUSCAE
Pereira, C. B.; Ortega, V. G.; Monte-Lima, I.
We present ultra-violet observations of the symbiotic star SY Mus obtained with IUE in 1996. The observations were timed to cover ingress and egress. We observe phase dependent intensity variations of the continuum and of the emission lines. These variations are caused by a wavelength dependent opacity with the characteristics of Rayleigh scatteri…