Search Publications
Proper motions of open clusters within 1 kpc based on the TYCHO2 Catalogue
Dias, W. S.; Lépine, J. R. D.; Alessi, B. S.
We present mean absolute proper motions of 112 open clusters, determined using the data from the Tycho2 Catalogue. For 28 clusters, this is the first determination of proper motion. The measurements made use of a large number of stars (usually several tens) for each cluster. The total number of stars studied in the fields of the 164 open clusters …
HST optical spectral index map of the jet of 3C 273
Meisenheimer, K.; Jester, S.; Röser, H. -J. +2 more
We present HST images at 622 nm and 300 nm of the jet in 3C 273 and determine the run of the optical spectral index at 0\farcs2 along the jet. The smoothness of spectral index changes shows that the physical conditions are varying smoothly across the jet. There is no correlation between the optical flux and spectral index, as would be expected for…
The complete ISO spectrum of NGC 6302
Waters, L. B. F. M.; Beintema, D. A.; Barlow, M. J. +6 more
We present the combined Infrared Space Observatory Short-Wavelength Spectrometer and Long-Wavelength Spectrometer 2.4-197 mu m spectrum of the Planetary Nebula NGC 6302 which contains in addition to strong atomic lines, a series of emission features due to solid state components. The broad wavelength coverage enables us to more accurately identify…
Transition region oscillations above sunspots
Fludra, A.
We present observations of three sunspots made in the EUV wavelength range with the Coronal Diagnostic Spectrometer (CDS) on SOHO. We examine time series of line intensities obtained with a 15-s cadence and calculate their Fourier power spectra and the wavelet transforms. We find oscillations in the chromosphere and transition region above sunspot…
Local clouds: Ionization, temperatures, electron densities and interfaces, from GHRS and IMAPS spectra of epsilon Canis Majoris
Jenkins, E. B.; Gry, C.
The composition and physical properties of several local clouds, including the Local Interstellar Cloud (LIC) in which the Sun is embedded, are derived from absorption features in the UV spectrum of the star epsilon CMa. We derive temperatures and densities for three components by combining our interpretations of the ionization balance of magnesiu…
High-resolution X-ray spectroscopy and imaging of supernova remnant N132D
Audard, M.; Behar, E.; Aschenbach, B. +4 more
The observation of the supernova remnant N132D by the scientific instruments on board the XMM-Newton satellite is presented. The X-rays from N132D are dispersed into a detailed line-rich spectrum using the Reflection Grating Spectrometers. Spectral lines of C, N, O, Ne, Mg, Si, S, and Fe are identified. Images of the remnant, in narrow wavelength …
The X-ray nebula of the filled center supernova remnant 3C 58 and its interaction with the environment
Bocchino, F.; Warwick, R. S.; Becker, W. +3 more
An XMM-Newton observation of the plerionic supernova remnant 3C 58 has allowed us to study the X-ray nebula with unprecedented detail. A spatially resolved spectral analysis with a resolution of 8'' has yielded a precise determination of the relation between the spectral index and the distance from the center. We do not see any evidence…
IRAS 09425-6040: A carbon star surrounded by highly crystalline silicate dust
Loup, C.; Yamamura, I.; Molster, F. J. +4 more
We present infrared spectroscopy and millimeter photometry and spectroscopy of the peculiar carbon star IRAS 09425-6040. The 2-15 mu m spectrum, as well as the CO millimeter line observations are typical for a (J-type) carbon star with moderate mass-loss rate. The 15-45 mu m spectrum is dominated by strong emission bands from Mg-rich and Fe-poor c…
Cassiopeia A: On the origin of the hard X-ray continuum and the implication of the observed O Viii Ly-alpha /Ly-beta distribution
Kaastra, J. S.; Vink, J.; Aschenbach, B. +4 more
We present the first results on the hard X-ray continuum image (up to 15 keV) of the supernova remnant Cas A measured with the EPIC cameras onboard XMM-Newton. The data indicate that the hard X-ray tail, observed previously, that extends to energies above 100 keV does not originate in localised regions, like the bright X-ray knots and filaments or…
The origin of the runaway high-mass X-ray binary HD 153919/4U1700-37
Kaper, L.; de Bruijne, J. H. J.; Hoogerwerf, R. +3 more
Based on its Hipparcos proper motion, we propose that the high-mass X-ray binary HD 153919/4U1700-37 originates in the OB association Sco OB1. At a distance of 1.9 kpc the space velocity of 4U1700-37 with respect to Sco OB1 is 75 km s-1. This runaway velocity indicates that the progenitor of the compact X-ray source lost about 7 Ms…