Search Publications
How Many Active Galaxies and QSOs Will Future Space Missions Detect?
Spinoglio, Luigi; Malkan, Matthew A.; Andreani, Paola
Averaged spectral energy distributions (SEDs) of active and starburst galaxies, from the 12 µm sample in the local universe, and QSOs, from an optically selected sample at a mean redshift <z>=0.7, are built from optical, near-IR, and far-IR (FIR; IRAS and Infrared Space Observatory) photometric observations. These SEDs are then used to…
New detections of optical emission from kiloparsec-scale quasar jets
Cheung, C. C.; Wardle, J. F. C.; Chen, Tingdong +1 more
We report initial results from the detection of optical emission in the arcsecond-scale radio jets of two quasars utilizing images from the Hubble Space Telescope archive. The optical emission has a very knotty appearance and is consistent with synchrotron emission from highly relativistic electrons in the jet. Combining these observations with th…
A comparison of some astrometric catalogues with the use of stars with large proper motions
Yatsenko, A. I.; Ivanov, G. A.
Pairwise differences of positions and proper motions of stars from the catalogues HIPPARCOS, CMC11, FONAC, NPM1, and PPM were used to determine their random and systematic errors. A significant relationship between differences of coordinates and proper motions of stars and their B-V colour indices was found for some pairs of the catalogues.
Mars express orbit design
Hechler, M.; Yanez, A.
This paper gives a survey of the orbit design, mission analysis aspects for Mars Express, the ESA mission to Mars. The emphasis is on those features which are unconventional. These are: the launch window with only 9 flight programs on the Fregat launcher upper stage for 30 launch days, and the re-targeting and Planetary protection strategy during …
Close pairs of quasars with different redshifts: New observations and results
Surdej, J.; Iovino, A.; Lee, D. W. +4 more
Burbidge et al. (\cite {burbidge}) argue that the observed number of quasar pairs with small angular separations and different redshifts (typically Delta theta <= 5 arcsec and Delta z > 0.1 ) is not compatible with a random distribution of quasars over the sky. After a brief review of all known quasar pairs with different redshifts, we show …
Ultraviolet Spectroscopy of the Massive LMC Multiple Systems Sk-67^0m#circ;18 (Br 5) and HD 36402 (Br 31)
Koenigsberger, G.; Auer, L. H.; Moffat, A. F. J.
Following previous IUE-based spectroscopic studies of WR+O binaries in the Galaxy and in the SMC, we present a similar study of the two systems, Br 5 [O3 If^*(+O) + O8-B0 I(+OB?)] and Br 31 [WC4(+O?) + O8 I:] in the Large Magellanic Cloud. We detect wind eclipse effects in the WC4+O (P = 3.033 d) pair in Br 31 similar to, but weaker than those obs…
Flares From the Giant ar 9433 on 24 April 2001
Uddin, Wahab; Chandra, Ramesh; Joshi, Anita
We present Hα CCD observations of three small-to-medium-size two-ribbon flares observed in the giant AR 9433 on 24 April 2001. Flare observations at other associated wavelengths (e.g., soft X-rays (SXR), hard X-rays (HXR), microwaves (MW)) obtained from archives are also presented and compared. We have tested the Neupert effect for the most energe…
Photometric study of the binary system NN Del
Gómez-Forrellad, J. M.; Sánchez-Bajo, F.; Corbera-Subirana, M. +2 more
We present the results of the differential V light curve analysis of NN Del. We show that NN Del is an EA eclipsing binary system with a period of 99.27 days and a highly eccentric orbit. Photometric solutions obtained using the Russell and the Wilson-Devinney models seem to indicate that both components are very similar in radii and luminosities …
Experimental studies of wave-particle interactions in space using particle correlators: Results and future developments
Gough, M. P.; Buckley, A. M.; Carozzi, T. +1 more
The technique of particle correlation measures directly electron modulations that result from naturally occurring and actively stimulated wave-particle interactions in space plasmas. In the past this technique has been used for studies of beam-plasma interactions, caused by both natural auroral electron beams via sounding rockets and by artificial…
A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars
Badiali, M.; Cardini, D.; Altamore, A. +2 more
We carry out an analysis of the Mg II 2796.34 Å emission line in RS CVn stars and make a comparison with the normal stars studied in a previous paper (Paper I). The sample of RS CVn stars consists of 34 objects with known HIPPARCOS parallaxes and observed at high resolution with IUE. We confirm that RS CVn stars tend to possess wider Mg II lines t…