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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…
Understanding the LMXB X2127+119 in M 15. II. The UV data
Margon, B.; Charles, P. A.; Ilovaisky, S. +4 more
We present HST UV observations of the high-inclination low mass X-ray binary AC211 (X2127+119), which is located in the globular cluster M 15 (NGC 7078). We have discovered a CIV P Cygni profile in this system, which confirms the existence of an outflow from AC211. The outflow velocity as measured from the P Cygni profile is =~ 1500 km s-1
V1432 Aql: A polar or an intermediate polar?
Singh, K. P.; Rana, V. R.
We present evidence for a spin period of 4070 s in a magnetic cataclysmic variable V1432 Aql, classified as a polar. The evidence is based on the analysis of archival X-ray data obtained from a 25 ks long and uninterrupted observations with XMM-Newton. We also detect modulation of the X-ray flux with the orbital period, various harmonics of the sp…
Speckle Observations of Composite Spectrum Stars. II. Differential Photometry of the Binary Components
Scardia, M.; Ginestet, N.; Prieur, J. -L. +6 more
Multicolor differential photometry measurements of the two components of 18 close binary stars, mostly composite spectrum stars, are presented. They are based on observations made at Pic du Midi Observatory with the speckle camera PISCO between 1993 and 1998. Optical bench experiments were also performed to assess the validity of the whole process…
Hubble Space Telescope Observations of Three Very Young Star Clusters in the Small Magellanic Cloud
Mutchler, Max; Villaver, Eva; Shaw, Richard A. +1 more
We present Space Telescope Imaging Spectrograph (STIS) broadband imagery and optical slitless spectroscopy of three young star clusters in the Small Magellanic Cloud (SMC). MA 1796 and MG 2 were previously known as planetary nebulae and were observed as such in our Hubble Space Telescope (HST) survey. With the HST spatial resolution, we show that …
The warm absorber of the type 1 Seyfert galaxy H1419+480
Barcons, X.; Carrera, F. J.; Ceballos, M. T.
The bright type 1 Seyfert galaxy H1419+480 (z~ 0.072), whose X-ray colours from earlier HEAO-1 and ROSAT missions suggested a complex X-ray spectrum, has been observed with XMM-Newton. The EPIC spectrum above 2 keV is well fitted by a power law with photon index Γ= 1.84 +/- 0.01 and an Fe Kα line of equivalent width ~250 eV. At softer energies, a …
Structure and Evolution of the Transition Region Network Observed in he ii λ304
Venkatakrishnan, P.; Ravindra, B.
The length scale and life time of the transition region network cells were studied using He ii λ304 filtergrams. The temporal structure function was calculated from spatially aligned He ii λ304 images. The estimated life time of the network cell was about 27 hr. We compared this life time with the life time of photospheric magnetic network and of …
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations
Janhunen, P.; Lester, M.; André, M. +10 more
We analyse a conjunction event of the Cluster II spacecraft with the MIRACLE ground-based instrument net-work in northern Fennoscandia on 6 February 2001, between 23:00 and 00:00 UT. Shortly after the spacecraft were located at perigee, the Cluster II satellites’ magnetic footpoints move northwards over Scandinavia and Svalbard, almost perfectly a…
In-flight calibrations of IBIS/PICsIT
Foschini, L.; Di Cocco, G.; Malaguti, G. +6 more
PICsIT (Pixellated Imaging CaeSium Iodide Telescope) is the high energy detector of the IBIS telescope on-board the INTEGRAL satellite. It consists of 4096 independent detection units, ~ 0.7 cm2 in cross-section, operating in the energy range between 175 keV and 10 MeV. The intrinsically low signal to noise ratio in the gamma-ray astron…