Search Publications
η Carinae: The optical flare-like events during low-excitation passages
Sterken, C.; van Genderen, A. M.; Allen, W. H.
The 1992.5 and 1998.0 low-excitation events of the possible binary in the core of η Carinae show a conspicuous flare-like event in optical and near-ultraviolet light. These events last a couple of months and have a light amplitude of 0.1m-0.2m in V. Considering the presence of a dense (bi-polar) stellar wind, one explanation could be that some typ…
X-ray facility for the ground calibration of the X-ray monitor JEM-X on board INTEGRAL
Frontera, F.; Westergaard, N. J.; Lund, N. +12 more
We describe the X-ray facility developed for the calibration of the X-ray monitor JEM-X on board the INTEGRAL satellite. The apparatus allowed the scanning of the detector geometric area with a pencil beam of desired energy over the major part of the passband of the instrument. The monochromatic radiation is obtained with the use of a double cryst…
The RCW 114 nebula: An old supernova remnant or a WR wind-blown bubble?
Lallement, R.; Welsh, B. Y.; Sallmen, S. +1 more
We present medium resolution spectra (R ~ 7 km s-1) of the interstellar NaI D1 & D2 absorption lines observed towards 7 early-type stars with distances ranging from 221 to ~ 1.5 kpc in the line-of-sight to the RCW 114 nebula. Our observed pattern of absorption is in conflict with the findings of Bedford et al. (1984) who placed an u…
First INTEGRAL observations of eight persistent neutron star low mass X-ray binaries
Frontera, F.; Goldoni, P.; Santangelo, A. +16 more
Early results from the INTEGRAL Core Program, for a sample of eight persistently bright neutron star low mass X-ray binaries in the energy range from 5 keV to 200 keV, are presented. It is shown that INTEGRAL efficiently detects sources and that spectra may be obtained up to several hundreds of keV by combining data from three of the four INTEGRAL…
LBQS 1429-0053: A binary quasar rather than a lensed quasar.
Kneib, J. -P.; Faure, C.; Alloin, D. +3 more
Very deep ESO/VLT FORS1 and ISAAC images, as well as HST NICMOS2 data are used to infer the nature of the quasar pair LBQS 1429-0053 A and B, either a binary quasar or a doubly-imaged lensed quasar. Direct search of a putative lensing galaxy is unsuccessful down to R=27, J=24, Ks=22.5 and H=22.5. Moreover, no galaxy overdensity close to the quasar…
Mid-infrared images of the star forming region GGD 14 (IRAS 06084-0611)
Persi, P.; Tapia, M.
Mid-infrared images at 8.7, 9.7 and 12.5 mu m are presented of the star forming region GGD 14 associated with the source IRAS 06084-0611. In an area of ~ 30arcsec around the IRAS position, two mid-infrared sources were found. One was identified with the cometary compact HII region VLA 1 and the second with the faint and unresolved radio continuum …
Relation of transition region blinkers to the low chromosphere
Peter, H.; Brković, A.
We investigated the coupling between the low chromosphere, lower and upper transition region through the study of blinkers. Blinkers are extreme ultraviolet (EUV) small-scale transient brightenings best detected in transition region lines showing an intensity enhancement on the 60-100% level on average. We analysed time-series spectra of the \cii …
RX J004717.4-251811: The first eclipsing X-ray binary outside the Local Group
Pietsch, W.; Haberl, F.; Vogler, A.
The X-ray source
Variability of EUV-spectra from the quiet upper solar atmosphere: Intensity and Doppler shift
Peter, H.; Solanki, S. K.; Brković, A.
We have studied SUMER and CDS time series of spectra and images of quiet-Sun regions at the solar disc centre. The data contain ultraviolet emission lines sampling temperatures of the chromosphere, transition region and corona. We find a high correlation between average net Doppler shifts and relative brightness variabilities of the studied lines …
X-ray spectroscopy of UZ Librae
Gondoin, P.
UZ Librae is the giant primary of a close binary system with extremely fast rotation and revolution. Its distinctive characteristics include an optical light curve with a large amplitude and a high X-ray luminosity. UZ Librae was observed twice at five months interval in August 2000 and January 2001 by the XMM-Newton space observatory. Serie of li…