Search Publications
The ISOCAM/LW Detector Dark Current Behaviour
Okumura, K.; Sauvage, M.; Biviano, A. +5 more
We describe the calibration, measurements and data reduction, of the dark current of the ISOCAM/LW detector. We point-out the existence of two significant drifts of the LW dark-current, one throughout the ISO mission, on a timescale of days, another within each single revolution, on a timescale of hours. We also show the existence of a dependence …
Nonthermal Flare Emission from MEV-Energy Electrons at 17, 34, and 86 GHZ
Kundu, M. R.; White, S. M.; Shibasaki, K. +1 more
We present analyses of two solar flares observed with high spatial resolution at 86 GHz with the BIMA millimeter-wavelength telescope and at 17 and 34 GHz with the Nobeyama radioheliograph. The flares were observed on 1998 November 24 and 1999 May 1. At millimeter wavelengths these are impulsive events, and therefore they must be produced by MeV-e…
Properties and radial trends of coronal mass ejecta and their associated shocks observed by Ulysses in the ecliptic plane
McComas, D. J.; Forsyth, R. J.; Riley, Pete +1 more
In this paper, magnetic and plasma measurements are used to analyze 17 interplanetary coronal mass ejections (CMEs) identified by Ulysses during its in-ecliptic passage to Jupiter. We focus on the expansion characteristics of these CMEs (as inferred from the time rate of change of the velocity profiles through the CMEs) and the properties of 14 fo…
Using Hubble Space Telescope images to identify straight segments in galaxy nuclear spirals
Chernin, A. D.
This Letter reports the discovery of straight segments of nuclear spiral arms. Hubble Space Telescope images of Seyfert galaxies are used. The morphology of the straight features on scales of few hundred parsecs proves to be similar to the morphology of disc-wide polygonal spirals and rings. This suggests that the straight structures on both nucle…
An estimation of the shape and temporal variation of the solar wind sonic, Alfvénic and fast magnetosonic surfaces
Moussas, X.; Exarhos, G.
In this work we find the shape and dimension of the solar wind transition surfaces, namely the slow (sonic), the fast magnetosonic and the Alfvén surface, as a function of heliospheric latitude using actual experimental data from Ulysses spacecraft during its first pole to pole journey. We also give the temporal variation of the radius of these su…
Coronal mass ejections detected in solar mean magnetic field
Boberg, Fredrik; Lundstedt, Henrik
One minute resolution solar mean magnetic field sequences during 74 coronal mass ejection events are analyzed using wavelet transforms. A significant fraction of the resulting wavelet power spectra shows a characteristic peak at the time of the coronal mass ejection. With an average period of 13 minutes, the signature in the solar mean field is mo…
Distance and absorption features in the CG 30/CG 31/CG 38 complex
Knude, J.; Nielsen, A. S.
We report a possible confirmation of the short 200 pc distance to the cometary globules CG 30/31/38 suggested by a previously discussed (V - I) - V diagram to Vlim ~ 20 mag. New 2 magnitudes deeper V and I photometry centered on CG 31A indicate the presence of visual extinction A_V = 5\fm6 at 200 pc. In addition, we may have measured an…
Kinematics versus X-ray luminosity segregation in the Hyades
Makarov, V. V.
State of the art Tycho-2 proper motions of bona fide Hyades members are used in combination with the ROSAT X-ray survey of this open cluster in Stern et al. (1995) to study the internal velocity dispersion versus X-ray luminosity by the classical convergent point method. It is shown in this paper for the Hyades members with B-V below 0.7 mag that …
Interstellar Carbon Abundance
Gnacinski, Piotr
We present 10 new measurements of carbon gas phase column density in the interstellar medium. We have used spectra made with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope containing the CII 1334.5 Ang and CII* 1335.7 Ang lines. The continuum reconstruction method has been used to obtain the carbon column density from t…
Hubble Space Telescope Planetary Camera Imaging of HH 29
Bally, John; Morse, Jon; Devine, David +2 more
We present Hubble Space Telescope Hα and [S II] images of HH 29. The proximity of HH 29 (140 pc) and the high resolution of the Planetary Camera has resulted in the most detailed images obtained so far of any Herbig-Haro object. The most prominent feature is a linear Hα ridge leading the working surface of a bow shock with a chaotic trailing [S II…