Search Publications
A Cluster of Low-Redshift LYalpha Clouds toward PKS 2155-304. I. Limits on Metals and D/H
Carilli, Chris; Shull, J. Michael; Stocke, John T. +4 more
We report observations from the Hubble Space Telescope (HST) and the VLA on the galactic environment, metallicity, and D/H in strong low-redshift Lyalpha absorption systems toward the bright BL Lac object PKS 2155-304. These studies are intended to clarify the origin and chemical evolution of gas at large distances from galaxies. With GHRS/G160M d…
A complete infrared Einstein ring in the gravitational lens system B1938+666.
Blandford, R. D.; Bremer, M. N.; Jackson, N. +7 more
We report the discovery, using NICMOS on the Hubble Space Telescope, of an arcsec-diameter Einstein ring in the gravitational lens system B1938 +666. The lensing galaxy is also detected, and is most likely an early-type galaxy. Modelling of the ring is presented and compared with the radio structure from MERLIN maps. We show that the Einstein ring…
The far infrared line spectrum of the protostar IRAS 16293-2422
Liseau, R.; White, G. J.; Ceccarelli, C. +7 more
We report mid-IR wavelength observations toward the low mass star forming region IRAS 16293-2422 between 45microns - 197microns with the Long Wavelength Spectrometer (LWS) on board ISO, and of the CI(609microns ) line observed with the JCMT. A map of the CII(157microns ) line shows that the region is relatively uncontaminated by Photo-Dissociation…
ISO observations of candidate young brown dwarfs
Torra, J.; Rieke, G. H.; Laureijs, R. J. +2 more
ISOCAM measurements or upper limits for low mass members of the rho Ophiuchi embedded cluster extend the sampling of the spectral energy distributions already obtained from the ground towards longer wavelengths, where emission by circumstellar material is significant. Good fits to the combined (ground-based + ISOCAM) photometry are obtained with t…
Globular clusters in the blue compact galaxy ESO 338-IG04 (Tololo 1924-416), as tracers of the star formation history. Results from HST/WFPC2 observations
Oestlin, Goeran; Bergvall, Nils; Roennback, Jari
Multicolour images of the starbursting metal poor blue compact galaxy ESO 338-IG04 have been obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. In the images we find numerous point-like sources concentrated towards the main body of the galaxy, which we identify as globular cluster candidates. We show that these ob…
B0712+472: a new radio four-image gravitational lens
Muxlow, T. W. B.; Pearson, T. J.; Bremer, M. +14 more
A new four-image gravitational lens system, B0712+472, has been discovered during the Cosmic Lens All-Sky Survey. This system consists of four flat-spectrum radio images that are also seen on a Hubble Space Telescope (HST) image, together with the lensing galaxy. We present MERLIN, VLA and VLBA maps and WHT spectra of the system as well as the HST…
Center-to-limb line width measurements of solar chromospheric, transition region and coronal lines
Doyle, J. G.; Wilhelm, K.; Erdelyi, R. +1 more
Line widths derived from observational data obtained by SUMER onboard SOHO in August 1996 at disk center and at the limb are used to confront those derived via assuming Alfven and/or magneto-acoustic wave heating. The observational data clearly shows a center-to-limb variation in the upper chromospheric and transition region lines, with only a mar…
Long-lived giant cells detected at the surface of the Sun
Scherrer, P. H.; Duvall, T. L.; Beck, J. G.
Giant convective cells have been predicted to exist in the Sun. Such cells should span the entire zone unstable to convective motions - now known to cover the outer 29 per cent of the Sun's radius - and could be dredging up the magnetic flux that is thought to be the source of solar activity (sunspots). Several studies have failed to detect these …
Wide Field Planetary Camera 2 Observations of the Brown Dwarf Gliese 229B: Optical Colors and Orbital Motion
Kulkarni, S. R.; Golimowski, D. A.; Burrows, C. J. +2 more
Three-epoch observations of the M1 V-plus-brown dwarf system Gliese 229AB using the Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2) are reported. Relative astrometric measurements spanning 1 year confirm the common proper motion of the pair and reveal the first evidence of orbital motion. The radial and azimuthal components of Gl 22…
The equatorial disc of the Be star X Persei
Waters, L. B. F. M.; de Martino, D.; Boogert, A. C. A. +4 more
We study the long-term behaviour of the equatorial disc of the Be/X-ray binary X Persei (X Per), combining new low-resolution IUE spectra and IR photometry with UV, optical and IR observations collected from the literature. We find that the near-UV continuum level of X Per varies along with the optical brightness. From the UV observations, we also…