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Evidence for Galaxy Interactions/Mergers from Medium Deep Survey WFPC2 Data
Im, M.; Griffiths, R. E.; Ratnatunga, K. U. +3 more
We examine the morphological and statistical properties of close galaxy pairs from two sets of 28 WFPC2 fields, acquired for the Medium Deep Survey (MDS) and the Groth-Westphal Survey (GWS) in F606W (V) and F814W (I) passbands. In the GWS sample all fields have uniform 95% completeness down to I <~ 24.3 mag, whereas in the MDS sample, fields ha…
The Distance to the Coma Cluster from Surface Brightness Fluctuations
Baum, William A.; Hammergren, Mark; Thomsen, Bjarne +1 more
We report on the first determination of the distance to the Coma Cluster from surface brightness fluctuation (SBF) measurements obtained from Hubble Space Telescope WFPC2 observations of the bright E0 galaxy NGC 4881 in the Coma Cluster and ground-based observations of the ``standard'' E1 galaxy NGC 3379 in the Leo-I group. Relative distances base…
Imaging the nuclear environment of NGC 1365 with the Hubble Space Telescope
Boksenberg, Alec; Lindblad, Per Olof; Kristen, Helmuth +1 more
The region surrounding the active nucleus of the barred spiral galaxy NGC 1365 is observed in the [Oiii] lambda 5007 line and neighbouring continuum using the Faint Object Camera (FOC) aboard the Hubble Space Telescope (HST). In the continuum light numerous bright ``super star clusters'' (SSCs) are seen in the nuclear region. They tend to fall on …
Detection of SO2 on Callisto with the Hubble Space Telescope
Johnson, Robert E.; McGrath, Melissa A.; Noll, Keith S. +1 more
We have detected SO2 in ultraviolet spectra of Callisto obtained with the Hubble Space Telescope's Faint Object Spectrograph. An absorption band centered at 280 nm appears in the spectrum of Callisto's leading hemisphere, but is not apparent in the spectrum of the trailing hemisphere. The band is similar to the SO2 band on Eu…
A 200km/s molecular wind in the peculiar carbon star V Hya.
Jorissen, A.; Knapp, G. R.; Young, K.
A molecular wind with an outflow speed in excess of 200km/s has been found in the AGB carbon star V Hya. Observations of several molecular lines show that the circumstellar envelope is expanding at 15km/s and is flattened and inclined to the line of sight. The fast wind appears to be expanding from the poles of the envelope, with the expansion spe…
The Discovery of Mg II λ4481 in the White Dwarf EG 102: Evidence for Ongoing Accretion
Barstow, M. A.; Holberg, J. B.; Green, Elizabeth M.
Recent optical spectra of the DA3 white dwarf EG 102 clearly show a feature due to Mg II λ4481. This is the first spectroscopic detection of Mg in a DA star at a temperature of 20,000 K. The presence of this ion in the stellar photosphere poses a severe dilemma for the theory of radiative levitation, which predicts a vanishingly small equilibrium …
The Pele Plume (Io): Observations with the Hubble Space Telescope
Ballester, Gilda E.; McGrath, Melissa A.; Spencer, John R. +3 more
In July 1996, with the Hubble Space Telescope (HST), we observed the Pele plume silhouetted against Jupiter at a wavelength of 0.27µm, the first definitive observation of an Io plume from Earth. The height, 420 ± 40 km, was greater than any plume observed by Voyager. The plume had significantly smaller optical depth at 0.34 and 0.41µm, where it wa…
Hubble Space Telescope Spectrum of SN 1987A at an Age of 8 Years: Radioactive Luminescence of Cool Gas
Challis, Peter M.; Chevalier, Roger A.; Kirshner, Robert P. +1 more
The Hubble Space Telescope 2000-8000 Å spectrum of SN 1987A observed on 1995 January 7 (7.87 yr after the explosion) is dominated by Hα and UV lines, including Mg II-Mg I λ2825 (equal to Hα in luminosity), Fe II UV 2 (two-thirds the intensity of Hα), Fe II UV 3 (one-half the intensity of Hα), and a 3730 Å emission feature identified with a blend o…
High Velocity Features in the Orion Nebula
Hartigan, Patrick; O'Dell, C. R.; Bally, John +1 more
We have surveyed the inner 7' of the Orion Nebula for high velocity outflows with Fabry-Perot images in [S II] and [O III]. The new survey recovers all known HH objects in the region, and also reveals a number of new high velocity flows. New flows include (1) jets over an arcminute in length that extend from the center of the nebula to HH 202 in t…
Spectroscopy of Close Companions to Quasi-Stellar Objects and the Ages of Interaction-Induced Starbursts
Stockton, Alan; Canalizo, Gabriela
We present low-resolution absorption-line spectra of three candidate close (<3") companions to the low-redshift QSOs 3CR 323.1, PG 1700+518, and PKS 2135-147. The spectra were obtained with the Low-Resolution Imaging Spectrometer (LRIS) on the Keck telescopes and with the Faint Object Spectrograph on the University of Hawaii 2.2 m telescope. Fo…