Search Publications
Positions for the Outer Planets and Many of Their Satellites. V. FASTT Observations Taken in 2000-2001
Stone, Ronald C.
As part of an ongoing observing program with the Flagstaff Astrometric Scanning Transit Telescope (FASTT), this paper presents 1084 new equatorial positions taken in 2000-2001 for the outer planets Uranus, Neptune, and Pluto, as well as for 17 satellites of Jupiter-Neptune. All the positions were determined using differential reductions with refer…
Statistical Properties of Circumnuclear H II Regions in Nearby Galaxies
Alonso-Herrero, Almudena; Knapen, Johan H.
We analyze the statistical properties of the circumnuclear H II regions of a sample of 52 nearby galaxies (v<1000 km s-1) from archival HST/NICMOS H-band and Paα (1.87 µm) observations at unprecedented spatial resolutions of between 1 and 30 pc. We catalog H II regions from the continuum-subtracted Paα images and find H II regi…
The Red Stellar Population in NGC 1569
Leitherer, Claus; Greggio, L.; Tosi, M. +6 more
We present HST NICMOS photometry of the resolved stellar population in the dwarf irregular galaxy NGC 1569. The color-magnitude diagram (CMD) in the F110W and F160W photometric bands contains ~2400 stars with a formal photometric error <~0.1 mag down to mF110W~23.5 and mF160W~22.5. The fiducial photometry has a completenes…
Precise Masses for Wolf 1062 AB from Hubble Space Telescope Interferometric Astrometry and MCDonald Observatory Radial Velocities
McArthur, B. E.; Benedict, G. F.; Franz, O. G. +17 more
We present an analysis of astrometric data from Fine Guidance Sensor 3 (FGS 3), a white-light interferometer on HST, and of radial velocity data from two ground-based campaigns. We model the astrometric and radial velocity measurements simultaneously to obtain parallax, proper motion, and component masses for Wolf 1062 (Gl 748; M3.5 V). To derive …
NICMOS Coronagraphic Observations of 55 Cancri
Schneider, G.; Hines, D. C.; Becklin, E. E. +3 more
We present new near-infrared (1.1 µm) observations of the circumstellar environment of the planet-bearing star 55 Cancri. With these Hubble Space Telescope (HST) images we are unable to confirm the observation of bright scattered radiation at longer NIR wavelengths previously reported by Trilling and coworkers. NICMOS coronagraphic images wi…
Multiplicity of X-Ray-selected T Tauri Stars in Chamaeleon
Köhler, Rainer
We report on a multiplicity survey of a sample of X-ray-selected young stars in the Chamaeleon association. We used speckle interferometry and direct imaging to find companions in the separation range 0.13"-6". After correction for chance alignment with background stars, we find a multiplicity (number of binaries or multiples divided by number of …
Deep Hubble Space Telescope WFPC2 Photometry of M31's Thick Disk (?)
Sarajedini, Ata; Van Duyne, Jeffrey
We present deep color-magnitude diagrams (CMDs) for a field along the outer disk of M31 based on archival Hubble Space Telescope Wide Field Planetary Camera 2 observations in the F555W (~V) and F814W (~I) filters. The CMDs, which contain a total of about 50,000 stars, feature a prominent red giant branch (RGB) along with a significant population o…
Host Galaxies, Obscuration, and Nuclear Structure of Three Nearby Compact Symmetric Objects
Perlman, Eric S.; Stocke, John T.; Conway, John +1 more
We present three-band Hubble Space Telescope imaging of three nearby (z<=0.1) compact symmetric objects: 4C 31.04, 1946+708, and 1146+596. These objects were chosen on the basis of proximity to Earth as well as H I 21 cm line absorption. The inner H-band isophotes of these galaxies are well fitted by Nuker models, typical of nearby elliptical g…
A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction
Blair, William P.; Danforth, Charles W.; Raymond, John C.
The XA region of the Cygnus Loop is a complex zone of radiative and nonradiatve shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra, and a high-resolution long-slit Hα spectrum to study the spatial emission line variations across t…
Horizontal-Branch Morphology and Dense Environments: Hubble Space Telescope Observations of Globular Clusters NGC 2298, 5897, 6535, and 6626
Testa, Vincenzo; Iannicola, Giacinto; Buonanno, Roberto +4 more
HST observations of the core of four galactic globular clusters allowed us to obtain interesting clues about the influence of the environment on the star distribution along the horizontal branch. The chemical composition and the age of the target clusters have been derived through a detailed analysis of the (V,V-I) color-magnitude diagrams. The ph…