Search Publications
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…
Calcium to hydrogen line ratios in solar prominences
Heinzel, P.; Gouttebroze, P.
The ratio of Ca II 8542 Å to Hβ line intensities has been used for a long time to diagnose the gas pressure in solar prominences. In this paper we reconsider the theoretical dependence of E(8542)/E(Hβ ) on the gas pressure, as originally computed by Heasley & Milkey (1978), and extend this theoretical correlation to higher pressures. Firstly, …
ISO observations of low and moderate albedo asteroids. PHT-P and PHT-S results
Barucci, M. A.; Dotto, E.; Müller, T. G. +4 more
The ISO observations presented here are devoted to low and moderate albedo asteroids, which are supposed to be among the more primitive objects of the solar system. Spectroscopic and multi-filter photometric data of 77 Frigga, 114 Kassandra, 308 Polyxo, 511 Davida, and 914 Palisana have been obtained by the ISO instrument ISOPHOT. The subsystem PH…
The star cluster system of the NGC 7673 starburst
Gallagher, J. S., III; Homeier, N.; Pasquali, A.
We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16-33% of which are in bright star clusters. We identify 268…
Calibration of the distance scale from galactic Cepheids. I. Calibration based on the GFG sample
Musella, I.; Paturel, G.; Theureau, G. +3 more
New estimates of the distances of 36 nearby galaxies are presented based on accurate distances of galactic Cepheids obtained by Gieren et al. (1998) from the geometrical Barnes-Evans method. The concept of ``sosie'' is applied to extend the distance determination to extragalactic Cepheids without assuming the linearity of the PL relation. Doing so…