Search Publications
Boron in Lithium- and Beryllium-deficient F Stars
Deliyannis, Constantine P.; Lambert, David L.; Boesgaard, Ann Merchant +1 more
The Goddard High Resolution Spectrograph (GHRS) has been used with the Hubble Space Telescope (HST) to observe the B I region at 2497 Å in nine F and G dwarfs of approximately solar metallicity. The stars were selected because they have a variety of Li and Be deficiencies. Most of the nine stars were newly observed at high spectral resolution and …
The Optical Spectrum of the Geminga Pulsar
Halpern, Jules P.; Schiminovich, David; Martin, Christopher
We obtained an optical spectrum of the isolated pulsar Geminga at the Keck Observatory. The optical object is at the limit of spectroscopic capability of any telescope, with a continuum flux that is ~0.5% of the dark sky on Mauna Kea. With particular attention paid to the dominant systematics of sky subtraction in our observing and analysis method…
Solar Wind Consequences of a Coronal Hole Density Profile: Spartan 201-03 Coronagraph and Ulysses Observations from 1.15 Rsolar to 4 AU
Guhathakurta, Madhulika; Fisher, Richard
Spartan 201 is a small shuttle-launched and -retrieved satellite, whose mission is to study the origins of the solar wind. It carries on board two instruments, the Ultraviolet Coronal Spectrometer and the White-Light Coronagraph. The third mission of the Spartan 201 (1995 September 7-10) spacecraft was to provide a solar context for the in situ pa…
The 11B/10B Ratio of Local Interstellar Diffuse Clouds
Sofia, Ulysses J.; Federman, S. R.; Lambert, David L. +3 more
The isotopic ratio 11B/10B of gas in diffuse interstellar clouds toward ζ Oph, κ Ori, and δ Sco is measured using HST/Goddard High Resolution Spectrograph echelle spectra of the B II 1362 Å line. To within the errors of measurement, the three lines of sight give identical results for a mean value of 11B/10
Imaging and Spectroscopy of Arcs around the Most Luminous X-Ray Cluster, RX J1347.5-1145
Ferguson, Henry C.; Baum, Stefi A.; Kaiser, Mary Elizabeth +9 more
The cluster RX J1347.5-1145, the most luminous cluster in the X-ray wavelengths, was imaged with the newly installed Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. Its relatively high redshift (0.451) and luminosity indicate that this is one of the most massive of all known clusters. The STIS images unambiguously …
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…
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…
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…