Search Publications
Reactivation and Precise Interplanetary Network Localization of the Soft Gamma Repeater SGR 1900+14
Cline, T.; Hurley, K.; Kouveliotou, C. +5 more
In 1998 May, the soft gamma repeater SGR 1900+14 emerged from several years of quiescence and emitted a series of intense bursts, one with a time history unlike any previously observed from this source. Triangulation using Ulysses, BATSE, and KONUS data gives a 1.6 arcmin2 error box near the Galactic supernova remnant G42.8+0.6. This er…
Identification of beta -meteoroids from measurements of the dust detector onboard the ULYSSES spacecraft
Mann, I.; Wehry, A.
We investigate the detection of beta -meteoroids (i.e. dust particles that leave the Solar system in unbound orbits from the direction of the Sun) in the data set of the Ulysses dust experiment. Analysis of the detection geometry of the experiment for the time span from launch until the end of 1995 shows that the detection of beta -meteoroids is p…
Ultraviolet Interstellar Linear Polarization. V. Analysis of the Final Data Set
Martin, P. G.; Clayton, Geoffrey C.; Wolff, Michael J.
Using recent measurements of ultraviolet interstellar polarization, we have examined its relationship to ultraviolet extinction and to polarization and extinction measurements in the visible and infrared. The relationship between the relative amount of ultraviolet polarization and the parameter λmax, determined using only visible data, …
Determining the Physical Properties of the B Stars. I. Methodology and First Results
Fitzpatrick, Edward L.; Massa, Derck
We describe a new approach to fitting the UV-to-optical spectra of B stars to model atmospheres and present initial results. Using a sample of lightly reddened stars, we demonstrate that the Kurucz model atmospheres can produce excellent fits to either combined low-dispersion IUE and optical photometry or HST FOS spectrophotometry, as long as the …
The Age-dependent Luminosities of the Red Giant Branch Bump, Asymptotic Giant Branch Bump, and Horizontal Branch Red Clump
Sarajedini, Ata; Alves, David R.
Color-magnitude diagrams of globular clusters usually exhibit a prominent horizontal branch (HB) and may also show features such as the red giant branch (RGB) bump and the asymptotic giant branch (AGB) bump. Stellar evolution theory predicts that the luminosities of these features will depend on the metallicity and age of the cluster. We calculate…
Astrometric radial velocities. I. Non-spectroscopic methods for measuring stellar radial velocity
Lindegren, Lennart; Madsen, Søren; Dravins, Dainis
High-accuracy astrometry permits the determination of not only stellar tangential motion, but also the component along the line-of-sight. Such non-spectroscopic (i.e. astrometric) radial velocities are independent of stellar atmospheric dynamics, spectral complexity and variability, as well as of gravitational redshift. Three methods are analysed:…
Comet Halley's Gas Composition and Extended Sources: Results from the Neutral Mass Spectrometer on Giotto
Eberhardt, Peter
The Neutral Mass Spectrometer on the Giotto spacecraft established that H2O is the dominant species in Comet Halley's volatiles and determined the abundance of more than 10 parent species. The instrument discovered strong extended H2CO and CO sources in the coma of Comet Halley. Polymerized H2CO associated with the…
Distance to the Cygnus Loop from Hubble Space Telescope Imaging of the Primary Shock Front
Blair, William P.; Raymond, John C.; Long, Knox S. +1 more
We present a Hubble Space Telescope (HST) Wide Field Planetary Camera 2 narrowband Hα image of a region on the northeastern limb of the Cygnus Loop supernova remnant. This location provides a detailed example of where the primary blast wave first encounters the surrounding interstellar medium. The filament structure is seen in exquisite detail in …
Ultraviolet observations of Sirius A and Sirius B with HST-GHRS. an interstellar cloud with a possible low deuterium abundance
Koester, D.; Ferlet, R.; Vidal-Madjar, A. +4 more
We present new observations of the binary Sirius A / Sirius B performed with HST-GHRS. Two interstellar clouds are detected on this sightline, one of them being identified as the Local Interstellar Cloud (LIC), in agreement with previous HST-GHRS observations of Sirius A (Lallement et al. \cite{lalle}). The interstellar structure of this sightline…
ISOCAM data processing
Aussel, H.; Abergel, A.; Pantin, E. +6 more
The ISOCAM infrared camera is one of the four instruments on board the ISO (Infrared Space Observatory) spacecraft which was launched successfully on 1995 November 17. It operates in the 2.5 - 18 mu m range, and was developed by the ISOCAM consortium lead by the French Service d'Astrophysique of CEA Saclay. This paper presents different algorithms…