Search Publications
Interplanetary and Interacting Protons Accelerated in a Parallel Shock Wave
Laitinen, T.; Vainio, R.; Kocharov, L.
We present a test-particle model of diffusive shock acceleration on open coronal field lines based on one-dimensional diffusion-convection equation with finite upstream and downstream diffusion regions. We calculate the energy spectrum of protons escaping into the interplanetary space and that of protons interacting with the subcoronal material pr…
The Hubble Space Telescope Survey of BL Lacertae Objects. IV. Infrared Imaging of Host Galaxies
Calzetti, Daniela; Urry, C. Megan; O'Dowd, Matthew +2 more
The Hubble Space Telescope NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with the WFPC2 in the R band by Urry and coworkers and Scarpa and coworkers. Ten of the 12 BL Lacs are clearly resolved, and the detected host galaxies are large, bright ellipticals with average absolute magnitude …
Mid infrared emission of nearby Herbig Ae/Be stars
Prusti, T.; Siebenmorgen, R.; Müller, T. G. +1 more
We present mid IR spectro-photometric imaging of a sample of eight nearby (D <= 240 pc) Herbig Ae/Be stars. The spectra are dominated by photospheric emission (HR6000), featureless infrared excess emission (T Cha), broad silicate emission feature (HR5999) and the infrared emission bands (HD 97048, HD 97300, TY CrA, HD 176386). The spectrum o…
NLTE spectral analysis of the sdOB primary of the eclipsing binary system LB 3459 (AA Dor)
Rauch, T.
We present a spectral analysis of the sdOB primary star of the binary system
ISO results on bright Main Belt asteroids: PHT-S observations
Barucci, M. A.; Lellouch, E.; Crovisier, J. +8 more
Observations of asteroids have been performed by the ISO satellite with PHT-S. The aim of these observations was to investigate the physical and compositional properties of five bright Main Belt Asteroids (1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, and 52 Europa) in the spectral range 5.8-11.6 mu m. The Standard Thermal Model and a black-body fit have be…
Angle dependent partial frequency redistribution in the interplanetary medium at Lyman alpha
Quémerais, E.
We present here the results of a model of multiple scattering at Lyman alpha in the interplanetary medium. This paper uses the formalism of Angle Dependent Partial Frequency Redistribution which allows a computation of the actual line profile for a hydrogen velocity distribution taking into account actual local velocities and temperatures. This wo…
Lyman-α imaging of the SO2 distribution on Io
Ballester, Gilda E.; Wolven, Brian C.; Feldman, Paul D. +7 more
Imaging spectroscopy of Io in the ultraviolet (1160-1720 Å) was carried out with the Space Telescope Imaging Spectrograph on HST on three dates in October 1997 and August 1998. Among the initial results was the observation of concentrated regions of Hi Lyman-α flux near the poles of Io that exhibited a morphology and temporal variability different…
Constraints on the Evolution of S0 Galaxies in Rich Clusters at Moderate Redshift
Smail, Ian; Couch, Warrick J.; Jones, Lewis
We combine morphological classifications from deep Hubble Space Telescope (HST) imaging of a sample of three clusters at z=0.31 and a further nine clusters at z=0.37-0.56 with existing spectroscopic observations of their elliptical (E) and S0 populations, in order to study the relative spectral properties of these two galaxy types. We have also us…
NICMOS images of JVAS/CLASS gravitational lens systems
Jackson, N.; Browne, I. W. A.; Xanthopoulos, E.
We present Hubble Space Telescope (HST) infrared images of four gravitational lens systems from the JVAS/CLASS gravitational lens survey and compare the new infrared HST pictures with previously published WFPC2 HST optical images and radio maps. Apart from the wealth of information that we get from the flux ratios and accurate positions and separa…
The Large Magellanic Cloud Eclipsing Binary HV 2274: Fundamental Properties and Comparison with Evolutionary Models
Fitzpatrick, Edward L.; Guinan, Edward F.; Ribas, Ignasi +6 more
We are carrying out an international, multiwavelength program to determine the fundamental properties and independent distance estimates of selected 14th to 15th magnitude eclipsing binaries in the Large and Small Magellanic Clouds (LMC and SMC). Eclipsing binaries with well-defined double-line radial velocity curves and light curves provide valua…