Search Publications
The dynamics of an erupting prominence
Klein, K. -L.; Mouradian, Z.
Hα full disk observations and radio interferometry at decimetre and metre wavelengths are used to probe the dynamics of ejecta and electron acceleration during a solar eruptive event on 1990 September 14. An erupting prominence and a moving type IV radio source are shown to trace a common magnetic structure during its rise from ~ 10 Mm to 3 R…
A wavelet analysis of quasi-periodic variability across a solar coronal hole region
Bromage, B. J. I.; Marsh, M. S.; Walsh, R. W.
High time resolution (~13 s cadence) Solar and Heliospheric Observatory (SOHO) Coronal Diagnostic Spectrometer (CDS) Grazing Incidence Spectrometer (GIS) time series data is analysed for evidence of quasi-periodic variability in the solar corona. The observations are obtained from a GIS study of a coronal hole boundary region taken in October 1997…
Far-infrared spectroscopy across the asymmetric bipolar outflows from Cepheus A and L 1448
Smith, M. D.; Eislöffel, J.; Froebrich, D.
Bipolar outflows are driven from protostars within molecular cores. They drive into molecular clouds, generating shock waves whose molecular emission lines have been observed in the infrared with ISO. We present spectroscopic data for seven locations within two asymmetric outflows,
Near-infrared spectra of ISO selected Chamaeleon I young stellar objects
Gómez, M.; Persi, P.
We present 0.95-2.5 mu m moderate (R ~ 500) resolution spectra of 19 ISOCAM detected sources in the Chamaeleon I dark cloud. Thirteen of these stars are candidate very low mass members of the cloud proposed by Persi et al. (\cite{per00}) on basis of the mid-IR color excess. The sample also includes a bona-fide young brown dwarf (Cha Hα 1), a trans…
Temporal variability in the Doppler-shift of solar transition region lines
Doyle, J. G.; Madjarska, M. S.; Teriaca, L. +2 more
High cadence datasets taken in C III 977 Å, O VI 1032 Å and Ne VIII 720 Å were analysed in an effort to establish the extent of the variability in the Doppler-shift of typical mid-transition region lines. The shortest time-scale variability seems to occur in the network boundary regions where the line-shift can vary by 7-8 km s-1 in les…
Small scale structure in circumstellar envelopes and the origin of globules in planetary nebulae
Mauron, N.; Huggins, P. J.
We analyze the small scale structure in the circumstellar envelopes of NGC 7027 and IRC+10216, using high resolution optical images in dust scattered light. We use the observations to test the proposal that globules in planetary nebulae, typified by globules in the Helix nebula, originate in high density contrast proto-globules in the atmosphere o…
6-m telescope spectroscopic observations of the bubble complex in NGC 6946
Larsen, S. S.; Alfaro, E. J.; Richtler, T. +6 more
We describe the results of a long-slit spectroscopic study of an unusual star complex in the nearby spiral galaxy NGC 6946 using the SAO 6 m telescope and the Keck 10 m telescope. The complex resembles a circular bubble 600 pc in diameter with a young super star cluster (SSC) near the center. The kinematics of ionized gas is studied through Hα emi…
An erupting macrospicule. Characteristics derived from SOHO-CDS spectroscopic observations
Bromage, G. E.; Parenti, S.; Bromage, B. J. I.
We report results from the analysis of a sequence of SOHO/CDS observations obtained off-limb in the south polar coronal hole on 6 March 1998. Three successive data sets were obtained with the Normal Incidence Spectrometer (NIS), the first of which showed a jet-like feature visible in the chromospheric and low transition region lines. The morpholog…
Linear polarization of the O VI lambda 1031.92 coronal line. I. Constraints on the solar wind velocity field vector in the polar holes
Bommier, V.; Raouafi, N. -E.; Lemaire, P. +1 more
In the first part of the present work, we report on the determination of the linear polarization parameters of the O VI lambda1031 .92 coronal line (hereafter O VI D2). Spectropolarimetric observations done by the SUMER spectrometer on board the spacecraft SoHO during minimum activity of the solar cycle (March, 1996) in the south corona…
Resolving the compact H II regions in N160A with HST
Schaerer, D.; Heydari-Malayeri, M.; Charmandaris, V. +4 more
Using high-resolution imaging with the Hubble Space Telescope, we study the Large Magellanic Cloud H II region N160A and uncover several striking features of this complex massive star-forming site. The two compact high excitation H II, blobs (HEBs) A1 and A2 are for the first time resolved and their stellar content and morphology is revealed. A1, …