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Optical configuration for a micro-arcsecond astrometric interferometer in space

Vakili, F.; Segransan, D.; Thomas, E. +3 more

One of the ESA candidate cornerstone missions is dedicated to wide-angle astrometry and aims at dramatically increasing the accuracy of astrometric measurements and the limiting magnitude with respect to Hipparcos (ESA Symposium, Venice, 1997). This mission was initially designated by the acronym GAIA (Global Astrometric Interferometer for Astroph…

The AGNS and their host galaxies as seen in the mid-infrared

Cesarsky, C.; Sauvage, M.; Vigroux, L. +4 more

We present a new diagnostic diagram based on ISOCAMspectra (5-16 µm) to distinguish the emission inducedby the active galactic nucleus (AGN) from that associated with thestar formation activity. This diagnostic based on the mid-IRcontinuum and the Unidentified Infrared Band (UIB) intensity allowsus to estimate the relative importance of the …

Space Telescope Imaging Spectrograph Parallel Observations of the Planetary Nebula M94-20

Gull, Theodore R.; Plait, Philip

The planetary nebula M94-20 in the Large Magellanic Cloud was serendipitously observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope as part of the Hubble Space Telescope Archival Pure Parallel Program. We present spatially resolved imaging and spectral data of the nebula and compare them with ground-based data,…

The HST Imaging Survey of BL Lac Objects

Urry, C. Megan; Scarpa, Riccardo; Treves, Aldo +2 more

Variations of anomalous and galactic cosmic ray fluxes in the northern hemisphere:ULYSSES EPAC and KET observations

Kunow, H.; Fraenz, M.; Heber, Bernd +1 more

From beginning of 1995 to the end of 1997 the Ulysses spacecraft scanned a heliographic latitude range of 80 degrees in the northern hemisphere. In this paper we will discuss Ulysses Energetic Particle Composition Experiment (EPAC) and Ulysses COsmic and Solar Particle INvestigation Kiel Electron Telescope (KET) observations of different anomalous…

Formation and Evolution of E and S0 Galaxies from HST and Keck Studies of z∼ 0.3-1 Clusters

Franx, Marijn; van Dokkum, Pieter; Kelson, Daniel +1 more

We have witnessed a dramatic increase over the last five years in results on distant galaxies, in large part because of the high resolution imaging capability of HST, and the multiobject spectroscopic capability of the Keck telescopes. Our program to obtain wide-field, multi-color WFPC2 mosaics with HST of intermediate redshift clusters, and spect…

IUE Observations of the Pulsation of RY SGR

Holm, Albert V.

The correlation of the onsets of RY Sgr's deep minima with pulsational phase suggests that the formation of dust is somehow driven by the pulsation. Observations were obtained using the International Ultraviolet Explorer (IUE) to investigate whether every pulsation cycle is accompanied by the condensation of small amounts of dust. During the 46-da…

On the difference between low-ℓ p-mode frequencies seen in velocity and in intensity

Gavryusev, V. G.; Gavryuseva, E. A.

We compare the line profiles and frequencies of low ℓ=0, 1, 2 acoustic oscillations seen in observations in velocity (by the GOLF and GONG experiments) and in intensity (LOI instrument). Our study indicates that the systematic shift between the frequencies of low-ℓ pmodes in intensity and in velocity measurements recently discovered by Toutain and…

Hipparcos Versus GCVS Amplitudes of Non-Mira M-Type Giants

Hoffleit, Dorrit

A recent paper by Dumm and Schild deals with the determination of radii and masses for Hipparcos stars with non-Mira giant M-type spectra. Their list contains 350 stars, of which 205 are either verified or suspected variables, including 53 SR (semiregular) and 51 Lb (irregular) variables. The authors determined that the masses and radii of the non…

An ISO survey of possible water and hydroxyl IRASER transitions towards the star-forming regions W49, W3(OH) and Sgr B2M

Gray, M. D.; Yates, J. A.

We report ISO LWS observations towards the star-forming regions W49N, W3(OH) and Sgr B2M in LWS04 mode (high-resolution Fabry-Perot scans). Possible far-infrared laser emission was detected in a water line at 133.55µm towards W49N, but the spectral resolution was inadequate to establish firmly the nature of the emission. An additional water …