Search Publications
A search for solar g modes in the GOLF data
Baudin, F.; García, R. A.; Provost, J. +14 more
With over 5 years of GOLF data having some 90% continuity, a new attempt has been made to search for possible solar g modes. Statistical methods are used, based on the minimum of assumptions regarding the solar physics; namely that mode line-widths are small compared with the inverse of the observing time, and that modes are sought in the frequenc…
Two-dimensional electron density in the solar corona from inversion of white light images - Application to SOHO/LASCO-C2 observations
Lamy, P.; Quémerais, E.
We present here the inversion method which has been developed to derive the electron density in the Solar Corona from LASCO-C2 white light images. We discuss how our inversion scheme can be applied either to images of polarized brightness of the corona or images of total brightness after removal of the dust and stray light components. The outputs …
The XMM-Newton serendipitous survey . II. First results from the AXIS high galactic latitude medium sensitivity survey
Pérez-Fournon, I.; Motch, C.; Page, M. J. +25 more
We present the first results on the identifications of a medium sensitivity survey (X-ray flux limit 2x 10-14 erg cm-2 s-1 in the 0.5-4.5 keV band) at high galactic latitude ({\mid}b{\mid}>20deg) carried out with the XMM-Newton X-ray observatory within the AXIS observing programme. This study is being…
X-ray evidence for spectroscopic diversity of type Ia supernovae:. XMM observation of the elemental abundance pattern in M 87
Finoguenov, A.; Böhringer, H.; Arnaud, M. +2 more
We present the results of a detailed element abundance study of hot gas in M 87, observed by XMM-Newton. We choose two radial bins, 1'-3' and 8'-16' (8'-14' for EMOS; hereafter the central and the outer zones), where the temperature is almost constant, to carry out the detailed abundance measurements of O, Ne, Mg, Si, S, Ar, Ca, Fe and Ni using EP…
Solar p-modes from 1979 days of the GOLF experiment
Grec, G.; Salabert, D.; Gelly, B. +5 more
With the GOLF instrument onboard the SoHO observatory, 1979 days of full-disc Doppler velocity observations have been compiled into a study of p-mode properties. We develop a multi-step iterative method (MSIM) algorithm to access all p-mode parameters while minimizing any perturbating effect or cross-talk between parameters during their determinat…
Resolving subdwarf B stars in binaries by HST imaging
Heber, U.; Green, E. M.; Thejll, P. +2 more
The origin of subluminous B stars is still an unsolved problem in stellar evolution. Single star as well as close binary evolution scenarios have been invoked but until now have met with little success. We have carried out a small survey of spectroscopic binary candidates (19 systems consisting of an sdB star and late type companion) with the Plan…
The physical structure of Magellanic Cloud H II regions. II. Elemental abundances
van der Hulst, J. M.; Vermeij, R.
Based on a new data set of optical and infrared spectra described in Vermeij et al. (\cite{Ronald}), we analyse the gas-phase elemental abundances of a sample of H Ii regions in the Large and Small Magellanic Cloud. The combined optical and infrared data set gives us access to all the ionization stages of astrophysically important elements such as…
Element abundances in cool white dwarfs. II. Ultraviolet observations of DZ white dwarfs
Wolff, B.; Koester, D.; Liebert, J.
We present a small data base of homogeneously derived photospheric element abundances of DZ white dwarfs and related objects. Our previous investigations are supplemented with the analysis of ultraviolet spectra for nine white dwarfs. Of particular interest is the detection of Lalpha absorption in van Maanen 2 and a determination of the effective …
Constraining the cosmological parameters using strong lensing
Kneib, J. -P.; Soucail, G.; Golse, G.
We investigate the potential of using strong lensing clusters to constrain the cosmological parameters Omegam and Omegalambda. The existence of a multiple image system with known redshift allows, for a given (Omegam, Omegalambda) cosmology, absolute calibration of the total mass deduced from lens modelli…
Seismic tests for solar models with tachocline mixing
Antia, H. M.; Brun, A. S.; Chitre, S. M. +1 more
We have computed accurate 1-D solar models including both a macroscopic mixing process in the solar tachocline as well as up-to-date microscopic physical ingredients. Using sound speed and density profiles inferred through primary inversion of the solar oscillation frequencies coupled with the equation of thermal equilibrium, we have extracted the…