Search Publications
Disk and Bulge Morphology of WFPC2 Galaxies: The HUBBLE SPACE TELESCOPE Medium Deep Survey
Griffiths, Richard E.; Ratnatunga, Kavan U.; Ostrander, Eric J.
Quantitative morphological and structural parameters are estimated for galaxies detected in Hubble Space Telescope observations of WFPC2 survey fields. A modeling approach based on maximum likelihood has been developed for two-dimensional decomposition of faint undersampled galaxy images into components of disk and bulge morphology. Decomposition …
The ISO spectrum of the planetary nebula NGC 6302. II. Nebular abundances
Pottasch, S. R.; Beintema, D. A.
The ISO spectrum of NGC 6302 is used, in conjunction with the visible and ultraviolet spectrum, to determine the nebular composition. In addition to being considerably more accurate than previous determinations, the abundances of many more elements (and ions) can be found. A discussion of the previous evolution of the central star, in the light of…
The quiet Sun extreme ultraviolet spectrum observed in normal incidence by the SOHO coronal diagnostic spectrometer
Harrison, R. A.; Landini, M.; Innes, D. E. +10 more
The extreme ultraviolet quiet Sun spectrum, observed at normal incidence by the Coronal Diagnostic Spectrometer on the SOHO spacecraft, is presented. The spectrum covers the wavelength ranges 308-381 Ä and 513-633 Ä and is based on data recorded at various positions on the solar disk between October 1996 and February 1997. Datasets at twelve of th…
The Location of the Nucleus of NGC 1068 and the Three-dimensional Structure of Its Nuclear Region
Kishimoto, Makoto
The Hubble Space Telescope (HST) archival UV imaging polarimetry data of NGC 1068 are reexamined. Through an extensive estimation of the observational errors, we discuss whether the distribution of the position angles (P.A.s) of polarization is simply centrosymmetric or not. Taking into account the effect of a bad focus at the time of the observat…
The Top 10 List of Gravitational Lens Candidates from the HUBBLE SPACE TELESCOPE Medium Deep Survey
Griffiths, Richard E.; Ratnatunga, Kavan U.; Ostrander, Eric J.
A total of 10 good candidates for gravitational lensing have been discovered in the WFPC2 images from the Hubble Space Telescope (HST) Medium Deep Survey (MDS) and archival primary observations. These candidate lenses are unique HST discoveries, i.e., they are faint systems with subarcsecond separations between the lensing objects and the lensed s…
Spectroscopic identification of a galaxy at a probable redshift of z = 6.68
Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Pascarelle, Sebastian
The detection and identification of distant galaxies is an important goal of observational cosmology, as such galaxies are seen at a time when the Universe was very young. The development of new techniques and instrumentation permits the search for ever-fainter galaxies, and so aids attempts to determine when the first stars and galaxies formed. H…
Millimeter and some near infra-red observations of short-period Miras and other AGB stars
Blommaert, J. A. D. L.; Groenewegen, M. A. T.; Baas, F. +3 more
Millimeter observations of 48 oxygen- and 20 carbon-rich AGB Miras with periods shorter than 400 days are presented. In addition, observations of 14 O-rich and 15 C-stars with longer, or no known, periods have also been obtained. The detection statistics is as follows: in 12CO J=1-0 and 2-1 we observed 97 stars, and detected 66 in at le…
Deflection of the local interstellar dust flow by solar radiation pressure.
Grün, E.; Landgraf, M.; Augustsson, K. +1 more
Interstellar dust grains intercepted by the dust detectors on the Ulysses and Galileo spacecrafts at heliocentric distances from 2 to 4 AU show a deficit of grains with masses from 1×10-17 to 3×10-16kg relative to grains intercepted outside 4 AU. To divert grains out of the 2- to 4-AU region, the solar radiation pressure must…
A Gas-rich Nuclear Bar Fueling a Powerful Central Starburst in NGC 2782
Smith, Beverly J.; Jogee, Shardha; Kenney, Jeffrey D. P.
We present evidence that the peculiar interacting starburst galaxy NGC 2782 (Arp 215) harbors a gas-rich nuclear stellar bar feeding an M82-class powerful central starburst, from a study based on high-resolution interferometric CO (J=1-->0) data and optical BVR and Hα observations, along with available near-infrared (NIR) images, a 5 GHz radio …
Hubble Space Telescope Imaging of the Globular Clusters in the Fornax Cluster: Color and Luminosity Distributions
Forbes, Duncan A.; Brodie, Jean P.; Grillmair, Carl J. +1 more
We examine the luminosity and B-I color distribution of globular clusters for three early-type galaxies in the Fornax Cluster using imaging data from the Wide Field Planetary Camera 2 on the Hubble Space Telescope. The luminosity functions we derive are in most cases better than 50% complete down to B=26.6. We find that the color distributions of …