Search Publications
Direct Detection of the Close Companion of Polaris with the Hubble Space Telescope
Schaefer, Gail H.; Bond, Howard E.; Evans, Nancy Remage +5 more
Polaris, the nearest and brightest classical Cepheid, is a single-lined spectroscopic binary with an orbital period of 30 yr. Using the High Resolution Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST) at a wavelength of ~2255 Å, we have directly detected the faint companion at a separation of 0farcs17. A second …
a New View of the Super Star Clusters in the Low-Metallicity Galaxy SBS 0335-052
Hunt, Leslie K.; Johnson, Kelsey E.; Reines, Amy E.
We present a study of the individual super star clusters (SSCs) in the low-metallicity galaxy SBS 0335-052 using new near-infrared (near-IR) and archival optical Hubble Space Telescope observations. The physical properties of the SSCs are derived from fitting model spectral energy distributions (SEDs) to the optical photometry, as well as from the…
Spitzer Observations of Star Formation in the Extreme Outer Disk of M83 (NGC5236)
Meurer, Gerhardt R.; Calzetti, Daniela; Walter, Fabian +4 more
Spitzer Infrared Array Camera (IRAC) observations of two fields in the extended UV disk (XUV-disk) of M83 have been recently obtained, ~3 R HII away from the center of the galaxy (R HII = 6.6 kpc). Galaxy Evolution Explorer (GALEX) UV images have shown the two fields to host in situ recent star formation. The IRAC images are …
A Multi-Epoch HST Study of the Herbig-Haro Flow from XZ Tauri
Krist, John E.; Hester, J. Jeff; Stapelfeldt, Karl R. +3 more
We present nine epochs of Hubble Space Telescope optical imaging of the bipolar outflow from the pre-main-sequence binary XZ Tauri. Our data monitor the system from 1995 to 2005 and include emission line images of the flow. The northern lobe appears to be a succession of bubbles, the outermost of which expanded ballistically from 1995 to 1999 but …
Surface Brightness Profiles of Composite Images of Compact Galaxies at z ≃ 4-6 in the Hubble Ultra Deep Field
Hathi, N. P.; Keel, W. C.; Jansen, R. A. +4 more
The Hubble Ultra Deep Field (HUDF) contains a significant number of B-, V-, and i'-band dropout objects, many of which were recently confirmed to be young star-forming galaxies at z ≃ 4-6. These galaxies are too faint individually to accurately measure their radial surface-brightness profiles. Their average light profiles are potentially of great …
High Spatial Velocity Features in the Orion Nebula,
O'Dell, C. R.; Henney, W. J.
We have used widely spaced in time Hubble Space Telescope images to determine tangential velocities of features associated with outflows from young stars. These observations were supplemented by ground-based telescope spectroscopy, and from the resultant radial velocities, space velocities were determined for many outflows. Numerous new moving fea…
HD 148937: A Multiwavelength Study of the Third Galactic Member of the Of?p Class
Walborn, Nolan R.; Bond, Howard E.; Nazé, Yaël +3 more
Three Galactic O-type stars belong to the rare class of Of?p objects: HD 108, HD 191612, and HD 148937. The first two stars show a wealth of phenomena, including strong X-ray emission, light variability, and dramatic periodic spectral variability. We present here the first detailed optical and X-ray study of the third Galactic Of?p star, HD 148937…
Old Globular Clusters in Magellanic-Type Dwarf Irregular Galaxies
Georgiev, Iskren Y.; Goudfrooij, Paul; Puzia, Thomas H. +1 more
We have performed a search for old globular clusters (GCs) using archival F606W and F814W Hubble Space Telescope/Advanced Camera for Surveys images of 19 Magellanic-type dwarf Irregular (dIrr) galaxies. Those dIrrs reside in nearby (2-8 Mpc) associations of dwarf galaxies only. All dIrrs have absolute magnitudes fainter than or equal to that of th…
Globular Clusters in the Outer Galactic Halo: AM-1 and Palomar 14
Dotter, Aaron; Sarajedini, Ata; Yang, Soung-Chul
AM-1, at ~120 kpc, and Palomar 14 (Pal 14), at ~70 kpc, are two of the most distant Galactic globular clusters (GCs) known. We present Hubble Space Telescope Wide Field Planetary Camera 2 photometry of AM-1 and Pal 14 that reveals unprecedented depth and detail in the color-magnitude diagrams of these two clusters. Absolute and relative age measur…
A High Resolution View of the Jet Termination Shock in a Hot Spot of the Nearby Radio Galaxy Pictor A: Implications for X-Ray Models of Radio Galaxy Hot Spots
Bondi, M.; Brunetti, G.; Tingay, S. J. +1 more
Images made with the Very Long Baseline Array (VLBA) have resolved the region in a nearby (z = 0.035) radio galaxy, Pictor A, where the relativistic jet that originates at the nucleus terminates in an interaction with the intergalactic medium, a so-called radio galaxy hot spot. This image provides the highest spatial resolution view of such an obj…