Search Publications
Exploring the spectral properties of faint hard X-ray sources with XMM-Newton
Fiore, F.; Cappi, M.; Piconcelli, E. +3 more
We present a spectroscopic study of 41 hard X-ray sources detected serendipitously with high significance (>5sigma in the 2-10 keV band) in seven EPIC performance/verification phase observations. The large collecting area of EPIC allows us to explore the spectral properties of these faint hard X-ray sources with 2 < F2-10 < 80 …
Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun
Solanki, S. K.; Brković, A.; Schühle, U. +4 more
We present an analysis of 14 ultraviolet emission lines belonging to different atoms and ions observed inside polar coronal holes and in the normal quiet Sun. The observations were made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). This study extends previous investigations made with the Sola…
H2O in stellar atmospheres. II. ISO spectra of cool red giants and hydrostatic models
Kerschbaum, F.; Aringer, B.; Jörgensen, U. G.
We present 26 ISO-SWS spectra taken from a sample of 13 M-type Semiregular, Lb and Mira variables and covering the wavelength range between 2.36 and 5 mu m at a medium resolution. All of the studied objects show intense water bands producing a deep absorption dip around 2.5 mu m. Features of CO, OH, SiO and CO2 are also visible. Using t…
ISO LWS Spectra of T Tauri and Herbig AeBe stars
van Dishoeck, E. F.; Blake, G. A.; Chiang, E. I. +2 more
We present an analysis of ISO-LWS spectra of eight T Tauri and Herbig AeBe young stellar objects. Some of the objects are in the embedded phase of star-formation, whereas others have cleared their environs but are still surrounded by a circumstellar disk. Fine-structure lines of [OI] and [CII] are most likely excited by far-ultraviolet photons in …
Multi-wavelength spectrophotometry of EX Hydrae
Gänsicke, B. T.; Beuermann, K.; Reinsch, K. +1 more
We present phase-resolved infrared and optical spectrophotometry of the intermediate polar EX Hya supplemented by archival ultraviolet data. The spin-modulated emission from the accretion funnel and the emission from the accretion disk or ring contain substantial optically thin components. The white dwarf dominates the unmodulated flux in the ultr…
Strongly absorbed quiescent X-ray emission from the X-ray transient XTE J0421+56 (CI Cam) observed with XMM-Newton
Orlandini, M.; Parmar, A. N.; Boirin, L. +3 more
We have observed the X-ray transient XTE J0421+56 in quiescence with XMM-Newton. The observed spectrum is highly unusual being dominated by an emission feature at ~ 6.5 keV. The spectrum can be fit using a partially covered power-law and Gaussian line model, in which the emission is almost completely covered (covering fraction of 0.98 -0.06
The FERRUM Project: Experimental oscillator strengths of the UV 8 multiplet and other UV transitions from the y6P levels of Fe II
Nilsson, H.; Johansson, S.; Hibbert, A. +2 more
We report on experimental branching fractions (BFs) for 19 transitions from the three 3d5(6S)4s4p(3P) y6P levels in Fe II, measured in Fourier transform spectra of a Penning discharge lamp and a hollow cathode lamp. The transition wavelengths span the interval between 1600 and 2850 Å. Absolute oscillator…
The ISO-SWS post-helium atlas of near-infrared stellar spectra
de Graauw, T.; Feuchtgruber, H.; Salama, A. +11 more
We present an atlas of near-infrared spectra (2.36 mu m-4.1 mu m) of ~ 300 stars at moderate resolution (lambda /delta lambda ~ 1500-2000). The spectra were recorded using the Short-Wavelength Spectrometer aboard the Infrared Space Observatory (ISO-SWS). The bulk of the observations were performed during a dedicated observation campaign after the …
HST STIS observations of four QSO pairs
Surdej, J.; Cristiani, S.; Petitjean, P. +3 more
We present HST STIS observations of four quasar pairs with redshifts 0.84<zem<1.56 and angular separation 2-3 arcmin corresponding to ~ 1-1.5 h-150 Mpc transverse proper distance at z ~ 0.9. We study the distribution of velocity differences between nearest neighbor \transi{H}i Lyman-alpha absorption lines det…
Models for solar magnetic loops. II. Comparison with SOHO-CDS observations on the solar disk
Solanki, S. K.; Landini, M.; Brković, A. +2 more
The present work describes a detailed comparison between SOHO-CDS observations of active region loops with a static, isobaric loop model developed assuming a temperature-independent heating function in the energy balance equation and a variable loop cross-section. The loop model is described in Landini & Landi (2002). Observations of an active…