Search Publications

Postrefurbishment Mission Hubble Space Telescope Images of the Core of the Orion Nebula: Proplyds, Herbig-Haro Objects, and Measurements of a Circumstellar Disk

O'Dell, C. R.; Wen, Zheng

We report on observations of M42 made with the Hubble Space Telescope (HST) immediately after the successful repair and refurbishment mission. Images were made in the strongest optical emission lines of H I, (N II), and (O III) and in a bandpass close to V. In a previous paper, the term proplyd was introduced to describe young stars surrounded by …

Narrowband HST Images of M87: Evidence for a Disk of Ionized Gas around a Massive Black Hole

Kriss, Gerard A.; Bohlin, Ralph C.; Hartig, George F. +7 more

We present HST WFPC2 narrowband Hα + [N II] images of M87 which show a small disk of ionized gas with apparent spiral structure surrounding the nucleus of M87. The jet projects ~19.5^deg^ from the minor axis of the disk, which suggests that the jet is approximately normal to the disk. In a companion Letter, Harms et al. measure radial velocities a…

An IUE Survey of Interstellar H i LY alpha Absorption. I. Column Densities

Savage, Blair D.; Diplas, Athanassios

We measure Galactic interstellar neutral hydrogen column densities by analyzing archival interstellar Ly alpha absorption line data toward 554 B2 and hotter stars observed at high resolution with the IUE satellite. This study more than doubles the number of lines of sight with measures of N(H I) based on Ly alpha. We have included the scattered li…

The Abundant Elements in Interstellar Dust

Savage, Blair D.; Sofia, Ulysses J.; Cardelli, Jason A.

We explore the incorporation of the cosmically abundant species O, C, N, Mg, Si, Fe, and S into interstellar dust. Column densities based on Goddard High Resolution Spectrograph 3.5 km/s resolution measurements from the literature for eight individual absorbing regions toward five lines of sight are used. Corrections are applied as needed in order…

HST Photometry of the Trapezium Cluster

Stauffer, John R.; Prosser, Charles F.; Hartmann, Lee +4 more

We have obtained images of 11 fields in the Trapezium cluster with the Planetary Camera (PC) of the Hubble Space Telescope (HST) in order to extend Herbig & Terndrup's (1986) study of this prototype, dense embedded cluster to fainter magnitudes than is possible from the ground. Using these images, we have identified 319 stars within an area of…

Interstellar dust in the heliosphere

Mann, I.; Morfill, G. E.; Gruen, E. +5 more

A flow of µm-sized interstellar grains has been identified with the Ulysses dust detector in the outer solar system at about 5 AU from the Sun. The observed flux is 1.5x10^-4^m^-2^/s of particles of mean mass 3x10^-13^g, which corresponds to a mass flux of 5x10^-17^g/m^2^/s. The particles on hyperbolic trajectories have radiants which are co…

Massive Star Populations in Nearby Galaxies

Conti, Peter S.; Maeder, André

Multiwavelength Tests of the Dusty Torus Model for Seyfert Galaxies

Mulchaey, John S.; Wilson, Andrew S.; Kinney, Anne L. +5 more

We present a compilation of emission properties for a sample of 116 Seyfert galaxies based on both previously unpublished data and measurements available in the literature. These measurements include fluxes in the emission lines [O III] λ5007 and Hβ, as well as the infrared (25-60 microns), ultraviolet (1450 A), soft (0.2-4 keV), and hard (2-10 ke…

Morphological Studies of the Galaxy Populations in Distant ``Butcher-Oemler'' Clusters with HST. I. AC 114 at Z = 0.31 and Abell 370 at Z = 0.37

Smail, Ian; Ellis, Richard S.; Sharples, Ray M. +1 more

We present the first results of an ongoing program we are undertaking with the Wide Field Camera of the Hubble Space Telescope (HST) to understand the physical origin of the enhanced star formation seen in moderate-redshift (z ~ 0.3-0.4) cluster galaxies. Deep HST exposures have been obtained for the central regions of two rich compact "Butcher- O…

Hubble Space Telescope Imaging of Super--Star Clusters in NGC 1569 and NGC 1705

O'Connell, Robert W.; Gallagher, John S., III; Hunter, Deidre A.

We examine the structural properties of three super-star clusters in the nearby, H I-rich galaxies NGC 1569 and NGC 1705. The clusters, which have total absolute V magnitudes between - 13.3 and - 14.1, appear to be point sources on ground-based images but are partially resolved in new images obtained with the Hubble Space Telescope (HST) Planetary…