Search Publications

The Red Horizontal-Branch Star HD 17072

Lee, Jae-Woo; Carney, Bruce W.; Habgood, Michael J.

We summarize the results of a spectroscopic analysis of HD 17072, finding it to be a metal-poor ([Fe/H] = -1.17) red horizontal-branch star with T_eff = 5375 K and log g = 2.4. We also derive a radial velocity of 62.8 km s^-1. It has the best determined Hipparcos trigonometric parallax among the metal-poor field horizontal-branch stars and support…

First Results from the ISO-IRAS Faint Galaxy Survey

Neugebauer, Gerry; Soifer, B. T.; Elbaz, David +16 more

We present the first results from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12 µm ISOCAM and 90 µm ISOPHOT observations. As of 1997 October, over 500 s…

Optical positions of compact extragalactic radio sources with respect to the HIPPARCOS Catalogue

Costa, E.; Loyola, P.

Optical positions relative to the Hipparcos Catalogue, and therefore within the International Celestial Reference System (ICRS), have been obtained for the optical counterparts of 25 compact extragalactic radio sources (CERS) south of delta ~ +10degr . Most of these sources are being monitored as Benchmark objects for the establishment of a unifie…

AGN watch continuum monitoring of radio-quiet and radio-loud AGN

O'Brien, Paul T.; Leighly, Karen M.

The International AGN Watch has monitored a number of radio-quiet and radio-loud Active Galactic Nuclei - the most luminous objects in the universe. We present a review of the main observational results from the continuum monitoring campaigns, concentrating on those which aim to quantify the simultaneous ultraviolet to X-ray variability characteri…

A Recalibration of the Diffraction Efficiency of the Transmission Grating Spectrometers on EXOSAT

Kahn, Steven M.; Paerels, Frits; Wolkovitch, Debra N.

We describe a recalibration of the diffraction efficiency of the transmission gratings on EXOSAT. This recalibration is required in order to quantitatively interpret the soft X-ray spectra obtained with these instruments on Sco X-1. Because this source is extremely bright, the spectra are sensitive enough to reveal residual systematic effects in t…

STIS Signal-to-Noise Capabilities in the Ultraviolet

Kaiser, Mary Elizabeth; Kimble, Randy A.; Gilliland, Ronald L. +3 more

The Space Telescope Imaging Spectrograph (STIS) was designed as a versatile spectrograph for the Hubble Space Telescope (HST) capable of maintaining or exceeding the spectroscopic capabilities of both the Goddard High Resolution Spectrograph (GHRS) and the Faint Object Spectrograph (FOS) over the broad bandpass extending from the ultraviolet (115 …

Dust Disks around Main Sequence Stars

Stencel, R. E.; Backman, D. E.; Fajardo-Acosta, S. B. +1 more

Many nearby main sequence stars are surrounded by cool dust radiating strongly in the far-IR. The characteristics of some of the prototype systems will be discussed. The dust is understood to represent debris related to planet formation, and the known disk systems may be dense analogs of the Kuiper Belt structure in our outer solar system. ISO obs…

Ionized Outflows of Hot Stars

Waters, L. B. F. M.; Hillier, D. J.; Morris, P. W. +4 more

ISO-SWS Observations of Planetary Nebulae with [WR] Central Stars

Szczerba, R.; Tylenda, R.; Górny, S. K.

Synthetic Spectra for Carbon Stars from Dynamica Model Atmospheres

Aringer, Bernhard; Loidl, Rita; Hron, Josef +2 more