Search Publications
Properties of the SN 1987A Circumstellar Ring and the Distance to the Large Magellanic Cloud
Panagia, N.; Kirshner, R. P.; Macchetto, F. +2 more
We have determined the distance to SN 1987A by comparing the angular size of its circumstellar ring, measured from an HST image obtained in a narrow [O III] 5007 A filter, with its absolute size derived from an analysis of the light curves of narrow UV lines (N V λ1240, N IV] λ1486, N III] λ1750, and C III] λ1909) measured with IUE. Our analysis c…
HST Imaging of the Inner 3 Arcseconds of NGC 1068 in the Light of [O iii] lambda 5007
Ford, H. C.; Armus, L.; Evans, I. N. +3 more
We have used the Planetary Camera on board the Hubble Space Telescope to obtain a high spatial resolution [O III] λ5007 image of the nucleus of NGC 1068. This image resolves the narrow-line region into several distinct clouds arranged in an apparently conical geometry. The individual emission-line regions appear to be resolved, with sizes ~0.1" -0…
First Results from the Goddard High-Resolution Spectrograph: The Galactic Halo and the LY alpha Forest at Low Redshift in 3C 273
Savage, Blair D.; Morris, Simon L.; Gilliland, Ronald L. +1 more
We present results of initial spectroscopy using the Goddard High- Resolution Spectrograph and the Hubble Space Telescope on the bright low- redshift quasar 3C 273. We detect absorption lines produced by gas in the disk and halo of the Milky Way from numerous neutral and weakly ionized atoms and also from highly ionized atoms (Si IV, C IV, and N V…
The Ultraviolet Absorption Spectrum of 3C 273
Junkkarinen, V.; Schneider, D. P.; Jannuzi, B. T. +3 more
We identify six Lyα absorption systems with equivalent widths greater than 0.2 A in the ultraviolet spectrum of the nearby quasar 3C 273, more than expected on the basis of extrapolations of the observed number of Lyα clouds seen at large redshifts. Two Lyα lines appear to be produced by gas in the Virgo Cluster or by the halos of galaxies associa…
First Results from the Faint Object Camera: SN 1987A
Panagia, N.; Boksenberg, A.; Kirshner, R. P. +18 more
We present the first images of SN 1987A taken on day 1278 after outburst with the Faint Object Camera on board the Hubble Space Telescope. The supernova is well detected and resolved spatially in three broadband ultraviolet exposures spanning the 1500-3800 A range and in a narrow-band image centered on the [O III] λ5007 line. Simple uniform disk f…
Blue stragglers in the core of the globular cluster 47 Tucanae
Boksenberg, A.; Barbieri, C.; Weigelt, G. +18 more
High-resolution observations of the core of the globular cluster 47 Tucanae with the Faint Object Camera on the Hubble Space Telescope reveal a high density of 'blue straggler' stars, occupying the upper end of the main sequence from which all stars in the cluster should have long since evolved. Their presence in the dense core supports the hypoth…
The Imaging Performance of the Hubble Space Telescope
Faber, S. M.; Holtzman, Jon A.; Burrows, Christopher J. +4 more
Problems with the HST instantaneous imaging performance and pointing performance are discussed. Optical tests have clearly demonstrated that the HST suffers from spherical aberration. The top level specification was that 70 percent of the energy be focused in a 0.1 in. radius, but the present, and close to optimum, focus setting gives only about 1…
First Results from the Goddard High-Resolution Spectrograph: Elemental Abundances in the Diffuse Clouds toward XI Persei
Ebbets, Dennis C.; Sembach, Kenneth R.; Savage, Blair D. +4 more
An analysis is presented of high-resolution observations of ultraviolet interstellar absorption lines of dominant ion stages arising in the diffuse clouds toward Xi Per obtained with the Goddard High-Resolution Spectrograph. A detection of the weak intersystem line of semiforbidden C II 2325 A is reported. For C, O, and Mg, column densities are de…
Interstellar Gas Phase Abundance of Carbon, Oxygen, Nitrogen, Copper, Gallium, Germanium, and Krypton toward zeta Ophiuchi
Ebbets, Dennis C.; Savage, Blair D.; Cardelli, Jason A.
An analysis of weak (less than 10 mA) UV interstellar absorption line data obtained for the line of sight to the O9.5 IV star Zeta Oph is presented. Measurements of weak semiforbidden lines of N I, O I, Cu II, and a new UV detection of Na I are reported along with a small upper limit for C II. Interstellar detections of Ga II, Ge II, and Kr I are …
The Postcollapse Core of M15 Imaged with the HST Planetary Camera
Schneider, Donald P.; Lauer, Tod R.; Faber, S. M. +12 more
It is shown here that, despite the severe spherical aberration present in the HST, the Wide Field/Planetary Camera (WFPC) images still present useful high-resolution information on M15, the classic candidate for a cluster with a collapsed core. The stars in M15 have been resolved down to the main-sequence turnoff and have been subtracted from the …