Search Publications
First Results from HIPPARCOS
Kovalevsky, J.
After recalling the principle of the Hipparcos mission and of the data reduction, the main statistical features of the final Hipparcos and Tycho catalogues are presented. The results, characterized by accuracies in annual proper motions and parallaxes of the order of one milliarcsecond have been already widely used for astrophysical investigations…
A Candidate Protoplanet in the Taurus Star-forming Region
Padgett, D. L.; Van Buren, D.; Terebey, S. +2 more
Hubble Space Telescope/Near-Infrared Camera and Multiobject Spectrometer images of the class I protostar TMR-1 (IRAS 04361+2547) reveal a faint companion with 10.0"=1400 AU projected separation. The central protostar is itself resolved as a close binary with 0.31"=42 AU separation, surrounded by circumstellar reflection nebulosity. A long narrow f…
Detection of UIR bands in an isolated local interstellar cirrus cloud
Lemke, D.; Laureijs, R. J.; Lehtinen, K. +4 more
The unidentified infrared (UIR) emission bands at 7.7 and 11.3 mu m have been detected in the emission of an isolated cirrus cloud externally heated by the typical interstellar radiation field (ISRF) of the solar neighbourhood. For the observations we used ISOPHOT, the photometer aboard ISO. The detected UIR bands have absolute intensities ~ 1/100…
Deep Hubble Space Telescope/Planetary Camera Imaging of a Young Compact Radio Galaxy at Z = 2.390
Keel, William C.; Windhorst, Rogier A.; Pascarelle, Sam M.
We present deep 63-orbit Hubble Space Telescope/Planetary Camera images at ~0.06" FWHM resolution in the filters B450, V606, and I814--as well as in redshifted Lyα--of the radio source 53W002, a compact narrow-line galaxy at z=2.390 from the Leiden-Berkeley Deep Survey. These images allow us to distinguish several …
Network Coronal Bright Points: Coronal Heating Concentrations Found in the Solar Magnetic Network
Falconer, D. A.; Moore, R. L.; Porter, J. G. +1 more
We examine the magnetic origins of coronal heating in quiet regions by combining SOHO/EIT Fe XII coronal images and Kitt Peak magnetograms. Spatial filtering of the coronal images shows a network of enhanced structures on the scale of the magnetic network in quiet regions. Superposition of the filtered coronal images on maps of the magnetic networ…
MACHOs, White Dwarfs, and the Age of the Universe
Laughlin, Gregory; Freese, Katherine; Graff, David S.
A favored interpretation of recent microlensing measurements toward the Large Magellanic Cloud implies that a large fraction (i.e., 10%-50%) of the mass of the Galactic dark halo is composed of white dwarfs. However, a ground-based search by Liebert and a recent search of the Hubble Deep Field by Flynn did not detect a substantial dark halo popula…
ISO observations of Uranus: The stratospheric distribution of C_2H_2 and the eddy diffusion coefficient
Kessler, M. F.; Lellouch, E.; Feuchtgruber, H. +7 more
The infrared spectrum of Uranus has been recorded between 7 and 16.5mu m with the grating mode of the Short-Wavelength Spectrometer of ISO, with a resolving power of 1500. The 6-12mu m spectrum of Uranus has also been recorded at lower resolution (R=90) by the PHOT instrument in spectroscopic mode. The spectra show no signatures other than the C_2…
X-Rays from Superbubbles in the Large Magellanic Cloud. V. The H II Complex N11
Wakker, Bart P.; Chu, You-Hua; Smith, R. Chris +3 more
The giant H II complex N11 in the Large Magellanic Cloud contains OB associations at several different stages in their life histories. We have obtained ROSAT PSPC and HRI X-ray observations, Curtis Schmidt CCD images, echelle spectra in Hα and [N II] lines, and IUE interstellar absorption line observations of this region. The central bubble of N11…
The galactic globular cluster NGC 1851: its dynamical and evolutionary properties
Saviane, I.; Zaggia, S.; Piotto, G. +3 more
We have completely mapped the Galactic globular cluster NGC 1851 with large-field, ground-based VI CCD photometry and pre-repair HST/WFPC1 data for the central region. The photometric data set has allowed a V vs. (V-I) colour-magnitude diagram for ~ 20500 stars to be constructed. >From the apparent luminosity of the horizontal branch (HB) we de…
The Mid- and Far-Infrared Spectral Energy Distribution of Seyfert Galaxies
Rodriguez Espinosa, J. M.; Perez Garcia, A. M.; Santolaya Rey, A. E.