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ISO far-infrared observations of rich galaxy clusters. I. Abell 2670
Nørgaard-Nielsen, H. U.; Pedersen, K.; Hansen, L. +3 more
As part of an investigation of far-infrared emission from rich galaxy clusters the central part of Abell 2670 has been mapped with ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Point sources detected in the field have infrared fluxes comparable to normal spirals at the cluster distance. Probable optical counterparts are …
Interplanetary scattering effects in the jovian bKOM radio emission observed by ULYSSES
MacDowall, R. J.; Woan, G.; Barrow, C. H.
The scattering of radio waves by the interplanetary medium (subsequently referred to simply as `scattering') imposes limitations on measurements of fine temporal and angular structure at low radio frequencies. The jovian broad-band kilometric radiation (bKOM) is highly structured and observations of this emission, by the Unified Radio and Plasma E…
Geneva photometry of the Be star HR 1960: periodicity and extremely small amplitude
Burki, G.
The Be star HR 1960 has been monitored from 1982 to 1998 in Geneva photometry and from November 1989 to March 1993 by the Hipparcos satellite. This star shows two kinds of luminosity variation: i) The mean luminosity in V has slightly increased, by 5 millimags, during the survey (long-term variation); ii) A periodic light variation with a period o…
HD 30187 B and HD 39927 B: two suspected nearby hot subdwarfs in resolved binaries
Makarov, Valeri V.; Fabricius, Claus
In doing a B_T, V_T photometric solution for close Hipparcos double stars, based on the observations with the Tycho instrument of the Hipparcos satellite, we discovered two very blue subluminous components of HD 30187 and HD 39927. The position of the components on an observational HR diagram implies their being sdO or sdB hot subdwarfs. The only …
Low frequency plasma turbulence and high energy particles at CIR-related shock waves
Claßen, H. -T.; Mann, G.; Forsyth, R. J. +1 more
We present initial results from a survey of the low frequency magnetic field turbulence measured at the forward/reverse shock pairs associated with the interaction regions of high and low speed solar wind streams (CIRs). The magnetic field data are taken from vector helium and fluxgate magnetometer observations (VHM/FGM) aboard the Ulysses spacecr…
Atomic silicon towards the Orion-KL nebula
Walmsley, C. M.; Pineau des Forêts, G.; Gry, C.
We have used the Long Wavelength Spectrometer (LWS) on board ISO to observe the fine structure lines of atomic silicon at 68.5 and 129.7 microns towards the Orion Kleinmann-Low nebula. Our data show evidence for the detection of the J=2-1 transition at 68.5mum with a signal-to-noise ratio of 5. We consider the formation of the observed emission li…
The photometric variability of the Be star NW Serpentis
Harmanec, P.; Percy, J. R.; Marinova, M. M. +1 more
{NW Ser} is a bright (V = 6.1 - 6.2) active Be star which is known to vary photometrically on a time scale of hours to days. Using both Hipparcos and ground-based photometry, and using light curve, autocorrelation, power spectrum analysis and phase dispersion minimalization techniques, we have concluded that the period is close to 0.46d - a period…
Fast solar wind acceleration by Alfvén waves: observable effects on the EUV lines detected by SOHO/UVCS
Orlando, S.; Peres, G.; Spadaro, D. +1 more
SOHO/UVCS observations of the most intense EUV spectral lines emitted by the solar corona have been providing us a good opportunity to study in detail the acceleration regions of the solar wind. In this work we aim at deriving useful diagnostics and identifying possible signatures of Alfvén waves momentum deposition. More specifically we investiga…
IRAS 17393-3004, a late-type supergiant surrounded by a dust shell
Zylka, R.; Tuffs, R. J.; Philipp, S. +1 more
Infrared observations of IRAS 17393-3004, including a full scan ISOSWS are presented. The ISOSWS spectrum shows two prominent dust emission peaks at lambda 10.4mu m and 17.5 mu m confirming that the source is a luminous star surrounded by a dust shell. The spectrum of the star, deduced from modeling of the radiative transfer through a spherical sh…
Time-resolved spectroscopyHiifill of the peculiar Hα variable Be star HD 76534
Drew, Janet E.; Oudmaijer, René D.
We present time-resolved spectroscopy of the Be star HD 76534, which was observed to have an Hα outburst in 1995, when the line went from photospheric absorption to emission at a level of more than two times the continuum within 2.5 hours. To investigate the short-term behaviour of the spectrum of HD 76534 we have obtained 30 spectra within two ho…