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The ROSAT all-sky survey catalogue of optically bright main-sequence stars and subgiant stars
Schmitt, J. H. M. M.; Voges, W.; Huensch, M.
We present X-ray data for all main-sequence and subgiant stars of spectral types A, F, G, and K and luminosity classes IV and V listed in the Bright Star Catalogue that have been detected as X-ray sources in the ROSAT all-sky survey; several stars without luminosity class are also included. The catalogue contains 980 entries yielding an average de…
The shape of the unidentified infra-red bands: analytical fit to ISOCAM spectra
Boulanger, F.; Cesarsky, D.; Ryter, C. +1 more
Modelling the unidentified infrared dust bands at 6.2 7.7, 8.6, 11.3, and 12.7 µm by Lorentz profiles is shown to produce excellent fits to the spectra obtained with the Continuous Variable Filter (CVF) of the instrument ISOCAM, on-board the Infrared Space Observatory (ISO). The feature pedestals are accounted for by the wide wings of the Lo…
Rotating Transition Region Features Observed with the SOHO Coronal Diagnostic Spectrometer
Mason, H. E.; Pike, C. D.
Strong evidence has been found from SOHO-CDS (Solar and Heliospheric Observatory - Coronal Diagnostic Spectrometer) observations to support the hypothesis that rotation plays a major role in the dynamics of transition region features. A comprehensive survey of the CDS daily synoptic rasters has been carried out to select dynamic events by searchin…
An Infrared Einstein Ring in the Gravitational Lens PG 1115+080
Peng, C. Y.; Keeton, C. R.; Kochanek, C. S. +5 more
Hubble Space Telescope observations of the gravitational lens PG 1115+080 in the infrared show the known zl = 0.310 lens galaxy and reveal the zs = 1.722 quasar host galaxy. The main lens galaxy G is a nearly circular (ellipticity ɛ < 0.07) elliptical galaxy with a de Vaucouleurs profile and an effective radius of Re<…
NICMOS Imaging of the Nuclei of Arp 220
Scoville, N. Z.; Evans, A. S.; Schneider, G. +8 more
We report high-resolution imaging of the ultraluminous infrared galaxy Arp 220 at 1.1, 1.6, and 2.22 µm with the Near-Infrared Camera and Multiobject Spectrometer on the Hubble Space Telescope. The diffraction-limited images at 0.1"-0.2" resolution clearly resolve both nuclei of the merging galaxy system and reveal for the first time a numbe…
Cold dust in the Andromeda Galaxy mapped by ISO
Lemke, D.; Haas, M.; Hippelein, H. +4 more
A complete 175 mu m map of the Andromeda galaxy (M31) at 1farcm 3 resolution shows the distribution of cold dust. It is dominated by a ring at 10 kpc radius supplemented by a faint outer one at 14 kpc. No clear spiral pattern is recognisable. The azimuthally averaged radial brightness profile is rather flat within the 10 kpc ring and decreases exp…
The Metallicity and Dust Content of HVC 287.5+22.5+240: Evidence for a Magellanic Clouds Origin
Sembach, Kenneth R.; Savage, Blair D.; Wakker, Bart P. +3 more
We estimate the abundances of S and Fe in the high-velocity cloud HVC 287.5+22.5+240, which has a velocity of 240 km s^-1 with respect to the local standard of rest and Galactic direction l ~ 287 deg and b ~ 23 deg. The measurements are based on UV absorption lines of these elements in the Hubble Space Telescope spectrum of NGC 3783, a background …
Discovery of a late-type stellar population associated with the Gould Belt
Schmitt, J. H. M. M.; Motch, C.; Guillout, P. +2 more
We report the detection of a late-type stellar population in the direction of the Gould Belt among stars found by cross-correlating the ROSAT All-Sky Survey with the Tycho catalog. Regions of the Gould Belt located between l = 195°\ and l = 15°\ exhibit a strong density enhancement of X-ray active stars with associated X-ray luminosities LX
Asymmetry in Velocity and Intensity Helioseismic Spectra: A Solution to a Long-standing Puzzle
Kosovichev, A. G.; Scherrer, P. H.; Schou, J. +1 more
We give an explanation for the opposite sense of asymmetry of the solar acoustic mode lines in velocity and intensity oscillation power spectra, thereby solving the half-decade-old puzzle of Duvall and coworkers. The solution came after comparing the velocity and intensity oscillation data of medium angular degree l obtained from the Michelson Dop…
Fine structure of the red giant clump from HIPPARCOS data, and distance determinations based on its mean magnitude
Salaris, Maurizio; Girardi, Leo; Groenewegen, Martin A. T. +1 more
The I-band brightness M_I of clump stars is a possible distance indicator for stellar populations. Investigations have shown that M_I is almost insensitive to the V-I colour within the clump. Based on this, it was assumed that M_I was insensitive to age and composition of the stellar population and therefore an ideal standard candle, which could b…