Search Publications
Spatial Variability in the Ratio of Interstellar Atomic Deuterium to Hydrogen. I. Observations toward δ Orionis by the Interstellar Medium Absorption Profile Spectrograph
Tripp, Todd M.; Jenkins, Edward B.; Sofia, Ulysses J. +2 more
Studies of the abundances of deuterium in different astrophysical sites are of fundamental importance to answering the question about how much deuterium was produced during big bang nucleosynthesis and what fraction of it was destroyed later. With this in mind, we used the Interstellar Medium Absorption Profile Spectrograph (IMAPS) on the ORFEUS-S…
An Abundance Analysis for Five Red Horizontal-Branch Stars in the Extremely Metal-rich Globular Cluster NGC 6553
Cohen, Judith G.; Carretta, Eugenio; Gratton, Raffaele G. +1 more
We provide a high-dispersion line-by-line abundance analysis of five red horizontal-branch (HB) stars in the extremely metal-rich Galactic globular cluster NGC 6553. These red HB stars are significantly hotter than the very cool stars near the tip of the giant branch in such a metal-rich globular cluster, and hence their spectra are much more amen…
Hubble Space Telescope Observations of Nearby Radio-Loud Early-Type Galaxies
Baum, Stefi A.; de Zeeuw, P. Tim; Verdoes Kleijn, Gijs A. +1 more
We present and analyze Hubble Space Telescope (HST) WFPC2 broad- and narrowband observations of the central regions of 19 nearby radio-loud early-type galaxies. Together with two more galaxies, they form a complete sample of Fanaroff and Riley Type I galaxies. We obtained V- and I-band images and narrowband images centered on the Hα+[N II] emissio…
The detection of dust in the central galaxies of distant cooling-flow clusters
Kneib, J. -P.; Ivison, R. J.; Smail, Ian +2 more
We present 850-µ observations with the SCUBA submillimetre (sub-mm) camera of the central galaxies in seven concentrated clusters of galaxies at redshifts between 0.19 and 0.41. We detect sub-mm emission from the central galaxies in the rich clusters A1835 and A2390, and present upper limits for the central galaxies in the remaining five clu…
The NICMOS Snapshot Survey of Nearby Galaxies
Colina, L.; Nota, A.; Calzetti, D. +19 more
We present ``snapshot'' observations with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on board the Hubble Space Telescope (HST) of 94 nearby galaxies from the Revised Shapley Ames Catalog. Images with 0.2" resolution were obtained in two filters, a broadband continuum filter (F160W, roughly equivalent to the H band) and a narro…
The Age Difference between the Globular Cluster Subpopulations in NGC 4472
Brodie, Jean P.; Huchra, John P.; Kissler-Patig, Markus +1 more
The age difference between the two main globular cluster subpopulations in the Virgo giant elliptical galaxy NGC 4472 (M49) has been determined using Hubble Space Telescope WFPC2 images in the F555W and F814W filters. Accurate photometry has been obtained for several hundred globular clusters in each of the two main subpopulations, down to more th…
Comparison between Predicted and Empirical ΔVbumpHB in Galactic Globular Clusters
Salaris, M.; Zoccali, M.; Bono, G. +2 more
We present observational estimates of ΔVbumpHB in a sample of 28 galactic globular clusters (GGCs) observed by the Hubble Space Telescope. The photometric accuracy and the sizable number of stars measured in each cluster allowed us to single out the red giant branch bump both in metal-poor and in metal-rich GGCs. Empirical va…
B2045+265: A New Four-Image Gravitational Lens from CLASS
Pearson, T. J.; Bremer, M.; Blandford, R. D. +14 more
We have discovered a new gravitational lens in the Cosmic Lens All-Sky Survey (CLASS). The lens B2045+265 is a four-image system with a maximum separation of 1.9". A fifth radio component is detected, but its radio spectrum and its positional coincidence with infrared emission from the lensing galaxy strongly suggest that it is the radio core of t…
CIR Morphology, Turbulence, Discontinuities, and Energetic Particles
Tsurutani, B. T.; Lucek, E.; Crooker, N. U. +18 more
Corotating interaction regions (CIRs) in the middle heliosphere have distinct morphological features and associated patterns of turbulence and energetic particles. This report summarizes current understanding of those features and patterns, discusses how they can vary from case to case and with distance from the Sun and possible causes of those va…
Physical properties of a coronal hole from a coronal diagnostic spectrometer, Mauna Loa Coronagraph, and LASCO observations during the Whole Sun Month
Fludra, A.; Gibson, S. E.; Biesecker, D. +2 more
Until recently [Guhathakurta and Fisher, 1998], inference of electron density distribution in the solar corona was limited by the field of view of white-light coronagraphs (typically out to 6 Rs). Now, for the first time we have a series of white-light coronagraphs (SOHO/LASCO) whose combined field of view extends from 1.1-30 Rs