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Magnetic field depressions in the solar wind
Fränz, M.; Horbury, T. S.; Burgess, D.
Depressions in the interplanetary magnetic field strength occur on a wide range of temporal scales, starting with magnetic holes with a duration of several seconds and extending to larger-scale structures of more than 30 min duration. Using the magnetic field measurements of the Ulysses spacecraft, we quantify the statistical significance of the o…
Discovery of a Symmetrical Highly Collimated Bipolar Jet in Hen 2-90
Sahai, Raghvendra; Nyman, Lars-Åke
Using the Hubble Space Telescope, we have obtained Hα imaging of the object Hen 2-90, which has long been classified as a planetary nebula (PN). We find that the morphology of Hen 2-90 does not look like that of any known PN, but resembles that of a classical young stellar object (YSO)-a bipolar nebula bisected by a flaring disklike structure and …
Comparison of Transient Network Brightenings and Explosive Events in the Solar Transition Region
Wang, Haimin; Chae, Jongchul; Schühle, Udo +2 more
The relation between transient network brightenings, known as blinkers, and explosive events is examined based on coordinated quiet Sun observations in the transition region line O V λ630 recorded by the Coronal Diagnostic Spectrometer (CDS), in the transition region line Si IV λ1402 recorded by the Solar Ultraviolet Measurements of Emitted Radiat…
Structure and Dynamics of the Corona Surrounding an Eruptive Prominence
Gopalswamy, N.; Hudson, H. S.; Hanaoka, Y.
We report on the 1997 December 14 prominence eruption event that was accompanied by eruptive signatures in X-rays, EUV and white light: coronal dimming, X-ray arcade formation , X-ray brightenings, EUV eruption, and a white light CME. The data used were obtained by the Nobeyama Radioheliograph, Yohkoh Soft X-ray Telescope (SXT) and SOHO/LASCO and …
VLBI imaging of the gravitational lens MG J0414+0534
Ros, E.; Alberdi, A.; Pérez-Torres, M. A. +5 more
We observed the quadruple gravitationally lensed image of MG J0414+0534 on 23 November 1997 with a global VLBI array at 8.4 GHz. We report wide-field imaging results of its four components at submilliarcsecond resolution, displaying complex core-like and jet-like extended structures. A simple model combining a singular isothermal ellipsoid to repr…
Two-dimensional modelling of optical Hubble Space Telescope and infrared tip-tilt images of quasar host galaxies
McLure, R. J.; Dunlop, J. S.; Kukula, M. J.
A description is given of the method used to extract quasar host-galaxy parameters from the deep Hubble Space Telescope (HST) quasar images presented by McLure, Dunlop and co-workers. We then give the results of extensive testing of this technique on a wide range of simulated quasar+host combinations spanning the redshift range of our HST study (0…
Far Ultraviolet Spectroscopic Explorer Observations of the Low-Redshift Lyβ Forest
Jenkins, Edward B.; York, Donald G.; Sembach, Kenneth R. +10 more
We describe a moderate-resolution (20-25 km s-1) Far Ultraviolet Spectroscopic Explorer (FUSE) study of the low-redshift intergalactic medium. We report on studies of seven extragalactic sight lines and 12 Lyβ absorbers that correspond to Lyα lines detected by Hubble Space Telescope (HST)/Goddard High Resolution Spectrograph and Space T…
ROSAT PSPC observations of T Tauri stars in MBM12 PSPC observations of T Tauri stars in MBM12
Neuhäuser, R.; Alcalá, J. M.; Stelzer, B. +4 more
We present the ROSAT PSPC pointed and ROSAT All-Sky Survey (RASS) observations and the results of our low and high spectral resolution optical follow-up observations of the T Tauri stars (TTS) and X-ray selected T Tauri star candidates in the region of the high galactic latitude dark cloud MBM12 (L1453-L1454, L1457, L1458). Previous observations h…
Local Fractional Frequency Shifts Used as Tracers of Magnetic Activity
Toomre, Juri; Hindman, Bradley; Haber, Deborah +1 more
Using data from SOI-MDI (Haber et al., 2000), we compute the local frequencies of high-degree p modes and f modes. The frequencies are obtained through ring-diagram mode fitting. The Dense-Pack data set consists of a mosaic of 189 overlapping tiles, each tracked separately at the surface rotation rate over 1664-min time intervals during the Dynami…
Lithium and rotation on the subgiant branch. II. Theoretical analysis of observations
de Laverny, P.; De Medeiros, J. R.; Charbonnel, C. +2 more
Lithium abundances and rotation, determined for 120 subgiant stars in Lèbre et al. (1999) are analyzed. To this purpose, the evolutionary status of the sample as well as the individual masses have been determined using the HIPPARCOS trigonometric parallax measurements to locate very precisely our sample stars in the HR diagram. We look at the dist…