Search Publications
``Chain'' Galaxies are Edge-on Low Surface Brightness Galaxies
Dalcanton, Julianne J.; Shectman, Stephen A.
Deep HST WFPC2 images have revealed a population of very narrow blue galaxies, which Cowie et al. have interpreted as being a new morphological class of intrinsically linear star forming galaxies at z = 0.5--3. We show that the same population exists in large numbers at low redshifts (z ~ 0.03) and are actually the edge-on manifestation of low sur…
Ultraviolet Imaging of NGC 3310: A Merger-driven Global Starburst
O'Connell, Robert W.; Bohlin, Ralph C.; Smith, Andrew M. +8 more
We present the first far-ultraviolet (FUV; lambda ~ 1500 A) image of the nearby peculiar SAB(r)bc galaxy NGC 3310. The small 15" (945 pc) diameter circumnuclear starburst ring is the most luminous structure, producing 30% of the total observed FUV luminosity. Diffuse emission from the inner disk (20" < R < 40") contributes another ~20% of th…
Hubble Space Telescope Observations of Planetary Nebulae in the Magellanic Clouds. IV. [O iii] Images and Evolutionary Ages
Ford, H. C.; Harrington, J. P.; Wood, P. R. +6 more
The Planetary Camera of the Hubble Space Telescope has been used to obtain images in the [O III] λ5007 line for a sample of 15 planetary nebulae in the Magellanic Clouds chosen to eliminate any selection bias in either excitation class or in flux [for log F(Hβ) > -13.7 ergs cm^-2^ s^-1^]. These images are used to derive the physical dimensions,…
Visible and Far-Ultraviolet WFPC2 Imaging of the Nucleus of the Galaxy NGC 205
Casertano, Stefano; Ballester, Gilda E.; Grillmair, Carl +15 more
We have imaged the nucleus of NGC 205 through the F555W and F160BW filters of WFPC2 on the high-resolution planetary camera (PC). The nucleus consists of a resolved cluster of stars extending 7" x 6". The projected radial distribution of surface brightness can be fitted by a Hubble law with a small core of FWHM 214 x 190 mas (0.74 x 0.66 pc). We f…
The Gaseous Sulfur Dioxide Abundance over Io's Leading and Trailing Hemispheres: HST Spectra of Io's C 1B 2--X 1A 1 Band of SO 2 near 2100 Angstrom
Trafton, L. M.; Caldwell, J. J.; Barnet, C. +1 more
We report ultraviolet HST/GHRS observations of Io's spectrum at opposite orbital elongations in the wavelength band 2095-2135 Å smoothed to an effective resolution of 3.7-4.1 Å. Gaseous SO2 absorption over Io's trailing sunlit hemisphere was found to be 37% stronger than over the leading sunlight hemisphere. The effective two-way path o…
Helical Strands in the Jetlike Narrow-Line Region of ESO 428-G14
Simpson, Chris; Bower, Gary A.; Wilson, Andrew S. +1 more
We present HST/WFPC2 images of the narrow-line region (NLR) of the Seyfert 2 galaxy ESO 428-G14 (0714-2914, M4-1). The NLR consists of many individual, thin strands, which are very closely related to the radio jet and produce a highly complex, yet ordered, structure. We find that the jet is two-sided, with a double helix of emission-line gas appar…
The Ultraviolet and X-Ray View of the Demise of Nova V1974 Cygni
Sonneborn, G.; Shore, Steven N.; Starrfield, Sumner
We present new data on the variations of the ultraviolet nitrogen lines during the late, optically thin stages of the outburst of V1974 Cygni. These show that, ~500 days after discovery, the ejecta reached maximum ionization and then started to recombine, coincident with the X-ray turnoff observed with ROSAT. We derive densities for the ejecta at …
The Translucent Molecular Clouds toward HD 154368. I. Extinction, Abundances, and Depletions
Snow, Theodore P.; van Dishoeck, Ewine F.; Black, John H. +5 more
We report the results of a comprehensive analysis of a line of sight observed using the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST), toward HD 154368, an 09.5 lab star located about 800 pc away. The line of sight intersects translucent interstellar cloud material, having a color excess E(B - V) = 0.82 and known …
Combined Ultraviolet-Optical Spectropolarimetry of the Magnetic White Dwarf GD 229
Liebert, James; Schmidt, Gary D.; Smith, Paul S. +1 more
Detailed flux and polarization spectra of the magnetic white dwarf GD 229 have revealed a host of new absorption features in the ultraviolet and rich detail in the polarization of the strong optical lines. However, hydrogen does not appear to be represented in the spectrum. Thus, the many peculiar features still elude identification, and the magne…
Properties of Star 2, One of the SN 1987A Companions, Derived from Hubble Space Telescope--Faint Object Spectrograph Observations
Panagia, N.; Kirshner, R. P.; Gilmozzi, R. +2 more
We present and discuss the Hubble Space Telescope Faint Object Spectrograph observations of Star 2, one of the two companions of SN 1987A, in the range 1200-8000 A. Our analysis, based on a comparison of the observed spectrum with spectra of O and B type stars and with model atmospheres, confirms that Star 2 is a B2III star. The extinction toward …