Search Publications
UVCS/SOHO Ion Kinetics in Coronal Streamers
Raymond, J. C.; Modigliani, A.; Ciaravella, A. +9 more
We made streamer observations with the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO) during the early part of 1998, which was a time of moderate solar activity. We present an empirical study of coronal ion kinetics using the line profiles from these observations. Our first and most striking result is …
Segregated optical-near-infrared colour distributions of Medium Deep Survey galaxies
Benitez, N.; Ferreras, I.; Martinez-Gonzalez, E. +1 more
We present a K survey of 29 fields covering approximately 90 arcmin^2 from the Medium Deep Survey (MDS) catalogue down to a completeness magnitude of K=18.0 (limiting magnitude K=19.0). The morphology obtained by the MDS team using high-resolution images from HST/WFPC2 along with our near-infrared (NIR) observations allows colour-magnitude and col…
Far-Infrared Polarization of the Quasar 3C 279
Laureijs, R. J.; Klaas, Ulrich; Clavel, Jean
We present the first far-infrared (FIR) polarization results of the OVV quasar 3C 279 obtained with ISOPHOT for two epochs in 1996 and 1997. We describe its integral polarization properties at a wavelength of 170 µm, where the source shows a maximum in its energy distribution. After a γ-ray flare in 1996 January, a polarization of 23% closel…
The distance to eight X-ray sources derived from HIPPARCOS observations
Dolan, Joseph F.; Clark, L. Lee
The parallaxes of eight galactic X-ray sources measured by Hipparcos are consistent with zero in all but two cases, 4U1145-619 (= Cen X-5) and HZ43. The parallax and proper motion measured for each of the others, including the Be/neutron star binaries X Per and A0535+26 and the massive X-ray binaries 4U0900-40, 4U1700-37, and Cyg XR-1, are consist…
The Boron Abundance of the Orion G-Dwarf Member BD -05°1317
Cunha, Katia; Smith, Verne V.; Lambert, David L.
The boron abundance is derived for the young Orion solar-type member BD -05°1317 from Hubble Space Telescope Goddard High Resolution Spectrograph spectra of the B I resonance lines near 2497 Å. The abundance of logɛ(B)=2.1+/-0.2 is ~0.6-0.7 dex below solar. As this young pre-main-sequence star has an undepleted lithium abundance, such a low boron …
Coronal heating events in high-cadence TRACE data
Walsh, Robert W.; Ireland, Jack; Wills-Davey, Meredith
On March 23rd 1999 a set of TRACE (Transition Region and Coronal Explorer) observations were taken in support of Solar and Heliospheric Observatory (SOHO) / TRACE Joint Observing Program 83. The program is designed to look for coronal heating mechanisms operating at high cadence and to observe their dynamical effects on coronal loop density, tempe…
The evolution from birth to decay of a short-lived active region
Schmieder, Brigitte; Démoulin, Pascal; Mandrini, Cristina H. +3 more
In the following paper we present results of the analysis of NOAA active region 7968, which was the target of a coordinated observing campaign involving the instruments aboard the Solar and Heliospheric Observatory (SOHO), Yohkoh, and ground-based observatories (Bialków, Pic du Midi, and Huairou). This active region was relatively short-lived, and…
The long-term behaviour of the pulsation periods and amplitudes of the β Cephei star 16 (EN) Lacertae
Pigulski, A.; Jerzykiewicz, M.
The blue-light observations of this pulsating and eclipsing variable (BCEP+EA) cover an interval from 1950 to 1992. The out-of-eclipse (that is, pulsational) variation contains three sinusoidal terms with variable amplitudes. In our 1996 paper (JP96), based on the 1950-1983 data, we showed that for the first two terms, having frequencies equal to …
Lensed galaxies in Abell 370. II. The ultraviolet properties of arclets and the star formation rate at high redshift
Kneib, J. -P.; Ellis, R. S.; Soucail, G. +1 more
We discuss the statistical properties of faint background galaxies detected in a deep Hubble Space Telescope ultraviolet (F336W) Wide Field Planetary Camera 2 image of the lensing cluster Abell 370 (z=0.37). By combining modelled field galaxy counts at this wavelength with a detailed mass model for the cluster, we develop techniques for predicting…
Young Stars and Nonstellar Emission in the Aligned Radio Galaxy 3C 256
Dickinson, Mark; Djorgovski, S. G.; McCarthy, Patrick J. +8 more
We present ground-based images of the z=1.824 radio galaxy 3C 256 in the standard BVRIJHK filters and an interference filter centered at 8800 Å, a Hubble Space Telescope image in a filter dominated by Lyα emission (F336W), and spectra covering rest-frame wavelengths from Lyα to [O III] λ5007. Together with published polarimetry observations, we us…