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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, …
Subaru optical observations of the old pulsar PSR B0950+08
Kawai, N.; Zharikov, S. V.; Shibanov, Yu. A. +6 more
We report the B band optical observations of an old (tau ~ 17.5 Myr) radiopulsar PSR B0950+08 obtained with the Suprime-Cam at the Subaru telescope. We detected a faint object, B=27fm07 +/-0.16. Within our astrometrical accuracy it coincides with the radio position of the pulsar and with the object detected earlier by Pavlov et al. (\cite{Pavlov})…
The complete far infrared spectroscopic survey of Herbig AeBe stars obtained by ISO-LWS
Benedettini, M.; Elia, D.; Lorenzetti, D. +4 more
The ISO-LWS archive has been systematically searched in order to obtain a complete far IR spectrophotometric survey of Herbig AeBe (HAEBE) stars. The investigated sample is constituted by 15 objects which, together with the 11 HAEBE we have published in two previous papers, represents about 25% of all the known HAEBE. This catalogue constitues an …
The inner solar corona seen by SUMER, LASCO/C1, and EIT: Electron densities and temperatures during the rise of the new solar cycle
Inhester, B.; Wilhelm, K.; Newmark, J. S.
Detailed investigations of the corona and the source regions of the solar wind have become possible with spectroscopic and imaging instruments on the Solar and Heliospheric Observatory (SOHO). We present observations in the extreme ultraviolet (EUV), pertinent to the generation of the slow solar wind, which were obtained by the Solar Ultraviolet M…
Optical monitoring of the gravitationally lensed quasar Q2237+0305 from APO between June 1995 and January 1998
Stanek, K. Z.; Malhotra, S.; Rhoads, J. E. +12 more
We present a data set of images of the gravitationally lensed quasar Q2237+0305, that was obtained at the Apache Point Observatory (APO) between June 1995 and January 1998. Although the images were taken under variable, often poor seeing conditions and with coarse pixel sampling, photometry is possible for the two brighter quasar images A and B wi…