Search Publications
Deep HST/FOC Imaging of the Central Density Cusp of the Globular Cluster M15
King, Ivan R.; Sosin, Craig
Using the Faint Object Camera on the repaired Hubble Space Telescope, we have observed two fields in the globular cluster M15:\ the central density cusp, and a field at r = 20''. These are the highest-resolution images ever taken of this cluster's dense core, and are the first to probe the distribution of stars well below the main-sequence turnoff…
Absolute Flux Distributions of Solar Analogs from the UV to the Near-IR
Colina, Luis; Bohlin, Ralph
The 0.225-2.695mu m absolute flux distributions of the solar analogs P041C, P177D, and P330E are presented. The ultraviolet and optical wavelength range from 0.225mu m to 0.825mu m is based on high signal-to-noise spectra obtained with the HST Faint Object Spectrograph (FOS). The spectra in the near-infrared longward of 0.825mu m are scaled versio…
Interstellar Gas in Low Mass Virgo Cluster Spiral Galaxies
Madden, Suzanne C.; Smith, Beverly J.
We have measured the strengths of the [C II] 158 mu m, [N II] 122 mu m, and CO (1 - 0) lines from five low blue luminosity spiral galaxies in the Virgo Cluster, using the Infrared Space Observatory and the NRAO 12m millimeter telescope. Two of the five galaxies have high L([C II])/L(CO) and L(FIR)/L(CO) ratios compared to higher mass spirals. Thes…
High-Resolution Imagery of BD + 30degree3639 and Its Dusty Halo
White, Stephen M.; Borkowski, Kazimierz J.; Harrington, J. Patrick +1 more
The planetary nebula BD +30\arcdeg3639 has been imaged by the Hubble Space Telescope through nine narrow-band filters. A high resolution radio map has been obtained with the VLA. Comparison of Hβ , Hα and radio images allow us to derive the point-to-point variations in both the extinction and the ratio of total to selective absorption. The extinct…
Observations of Structures in the Inner Coma of Chiron with the HST Planetary Camera
Samarasinha, Nalin H.; Buie, Marc W.; Mueller, Beatrice E. A. +2 more
We have obtained a series of images of 2060 Chiron with the HST Planetary Camera on 3 nights near its minimum geocentric distance in 1993 (Delta = 8.342 AU). Extended structure was visible within a radial distance of 0.3'' from the nucleus. We interpret the structure to be the bound ballistic atmosphere and exopause boundary (at R_e~ 1800 km) hypo…
Distance to the Coma Cluster and a Value for HO Inferred from Globular Clusters in IC 4051
Ajhar, Edward A.; Grillmair, Carl J.; Groth, Edward J. +4 more
We report HST-WFPC2 observations of the giant E2 galaxy IC 4051 located 14' east of the center of the Coma Cluster. Eight full-orbit exposures were obtained with the F606W filter, and two with the F814W filter. Counts of globular clusters (GCs) in 0.2-mag wide bins were made within the PC1 (f/28) frame, where faint GCs can be distinguished from no…
A New Pulsation Spectrum and Asteroseismology of delta Scuti.
Templeton, Matthew R.; Bradley, Paul A.; Guzik, Joyce A. +3 more
We present the results of a five-year Strömgren y photometric campaign on δ Scuti. Our data set consists of 6515 discrete differential magnitudes, and spans the period of 1983 June to 1988 September. We found the primary pulsation mode at 59.731129±0.000002 µHz, in close agreement with the frequency determination of Fitch (1976, IAU Colloqui…
High Spatial Resolution Near-Infrared Imaging of the Central Regions of M31
Doyon, R.; Davidge, T. J.; Rigaut, F. +1 more
H and K images with 0.15 arc sec angular resolution are used to probe the stellar content in the central 8 arcsec of M31. A large number of stars are detected, and the majority of these have K≥17.5 and H - K colors between 0 and 1. After correcting for differences in distance and reddening, the mean locus of the M31 (K,H- K) diagram is found to be…
Ultraviolet Photometry of Stars in the Compact Cluster R136 in the Large Magellanic Cloud
Massey, Philip; Lynds, Roger; Hunter, Deidre A. +2 more
We present ultraviolet photometry of stars in the Large Magellanic Cloud star cluster R136. The data were obtained with the refurbished Wide Field/Planetary Camera on the Hubble Space Telescope through an ultraviolet filter centered at 1750 Å (F170W). These data, combined with optical HST observations presented previously, are used to explore the …
UV Spectral Classification of O and B Stars in the Small Magellanic =
Bruhweiler, Frederick C.; Smith Neubig, Margaret M.
We present an ultraviolet classification system for 0 and B stars of the Small Magellanic Cloud (SMC). This system is defined by a set of standard, low resolution, International Ultraviolet Explorer (JUE) spectra. This UV classification system results from the development of spectral sequences demonstrating systematic patterus of UV spectral featu…