References of "Gosset, Eric"
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See detailNew observational results on the colliding wind WR+O binary WR 30a
Gosset, Eric ULg; Royer, P.; Rauw, Grégor ULg et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

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See detailNarrow-band photometry of the eclipsing WN7+O binary WR 22
Royer, P.; Rauw, Grégor ULg; Manfroid, Jean ULg et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

In the present paper, we discuss photometric observations of the February 1996 eclipse of the very massive WR+O binary WR 22. Our data were obtained with a set of narrow-band filters, specially designed ... [more ▼]

In the present paper, we discuss photometric observations of the February 1996 eclipse of the very massive WR+O binary WR 22. Our data were obtained with a set of narrow-band filters, specially designed for the study of WR stars. [less ▲]

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See detailX-Ray Spectroscopy with XMM: A New Powerful Tool to Determine Fundamental Parameters of Early-type Stars
Mewe, R.; Rauw, Grégor ULg; van der Hucht, K. A. et al

(1998)

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See detailESO & NOT photometric monitoring of the Cloverleaf quasar
Ostensen, R.; Remy, M.; Lindblad, P. O. et al

in Astronomy and Astrophysics. Supplement Series (1997), 126

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been ... [more ▼]

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been successfully analysed using two independent methods (i.e. an automatic image decomposition technique and an interactive CLEAN algorithm). The photometric results from the two methods are found to be very similar, and they show that the four lensed QSO images vary significantly in brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of the $D$ component presents some slight departures from the general trend which are very likely caused by micro-lensing effects. Upper limits, at the 99% confidence level, of 150 days on the absolute value for the time delays between the photometric lightcurves of this quadruply imaged variable QSO, are derived. This is unfortunately too large to constrain the lens model but there is little doubt that a better sampling of the lightcurves should allow to accurately derive these time delays. Pending a direct detection of the lensing galaxy (position and redshift), this system thus constitutes another good candidate for a direct and independent determination of the Hubble parameter. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook for the ESO and NOT observations together with photometric results for the Cloverleaf quasar. This long table can be accessed on the WWW at the URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html} [less ▲]

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See detailLa restauration de la Grande Lunette Méridienne de l'Observatoire de Cointe.
Gosset, Eric ULg

in Ciel (Le) (1997), 59

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See detailSurveys of ultraviolet-excess quasar candidates in large fields
Gosset, Eric ULg; Moreau, O.; Surdej, Jean ULg et al

in Astronomy and Astrophysics. Supplement Series (1997), 123

We describe the results of a survey for moderately bright quasars performed in a 20.6-square-degree field around the galaxy NGC 450. The quasar candidates were selected on the basis of their ultraviolet ... [more ▼]

We describe the results of a survey for moderately bright quasars performed in a 20.6-square-degree field around the galaxy NGC 450. The quasar candidates were selected on the basis of their ultraviolet excess: by comparative visual inspection of the double image of each single object on a U/B dual-exposure Schmidt photographic plate, 95 primary and 45 secondary quasar candidates were selected on the basis of their $U$ image being too bright. The spectroscopic identification of the primary candidates led to the discovery of 59 bona fide quasars (out of which 6 were previously known). The Palomar Schmidt plate was digitised using the MAMA measuring machine and the outcoming data reduced using ad hoc procedures. A photometric calibration allowed us to derive values for the limiting magnitudes and for the U-B index selection threshold of the survey. A catalogue containing 60 quasars is presented with accurate positions, magnitudes and additional information such as redshifts. We studied the spatial distribution of the objects and detected, for the quasars of our sample, a significant deviation from randomness in the form of a propensity to cluster in pairs on the celestial sphere with a typical scale of about 10 arcmin. We also formally detected a tendency towards a 3-D clustering, but this result is induced by a single pair of quasars. A forthcoming paper will deal with a similar work performed in a field around NGC 520; the latter field is located directly to the North of the present one and slightly overlaps it. Based on observations acquired at the Mount Palomar and Las Campanas Observatories as well as at the European Southern Observatory. Also based on Schmidt-plate digitisations performed with the MAMA measuring machine of C.A.I. (I.N.S.U., Paris). [less ▲]

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See detailSearch for Interacting Winds in the WN7 + O Binary WR 22
Rauw, Grégor ULg; Vreux, Jean-Marie ULg; Gosset, Eric ULg

in Revista Mexicana de Astronomia y Astrofisica Conference Series (1996, December 01)

We present new spectroscopic observations of the He I Lambda5876 line in WR22 which were obtained around periastron. These data show strong line profile variability. We use recently determined orbital ... [more ▼]

We present new spectroscopic observations of the He I Lambda5876 line in WR22 which were obtained around periastron. These data show strong line profile variability. We use recently determined orbital elements of WR22 to discuss the possibility of tidal interactions or of a colliding wind phenomenon affecting the outer parts of the Wolf-Rayet atmosphere. [less ▲]

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See detailExistence of a short period (3.5-4 hours) in the photometric variability of WR 66.
Rauw, Grégor ULg; Gosset, Eric ULg; Manfroid, Jean ULg et al

in Astronomy and Astrophysics (1996), 306

We report here on an independent detection of a short period (~4hours) in the photometric variations of WR66, thus confirming in broad terms the discovery by Antokhin et al.. In addition, we present the ... [more ▼]

We report here on an independent detection of a short period (~4hours) in the photometric variations of WR66, thus confirming in broad terms the discovery by Antokhin et al.. In addition, we present the first spectroscopic variability analysis for this star. A few peculiarities of the spectrum of WR66 are also discussed. Finally, we perform a brief examination of different possible origins of the phenomenon. [less ▲]

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See detailWR22: the most massive Wolf-Rayet star ever weighed.
Rauw, Grégor ULg; Vreux, Jean-Marie ULg; Gosset, Eric ULg et al

in Astronomy and Astrophysics (1996), 306

The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the ... [more ▼]

The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the orbit, formerly determined on the basis of photographic spectra. The high signal-to-noise ratio of our data also allows the detection of some weak absorption lines which, for the first time, can definitely be attributed to the companion. A study of their radial velocities gives a mass ratio of m_WR_/m_O_=2.78 leading to a minimum mass of 72M[SUB]sun[/SUB]_ for the WN7 star. The companion can be classified as a "late O" (O6.5-O8.5) star with a luminosity ratio of the system q=L_WR_^y^/L_O_^y^ at 5500A of about 8. The exceptionally high mass of the WN7 star and its high hydrogen mass-fraction suggest that WR22 is at the beginning of its Wolf-Rayet evolution. As a matter of fact, with such a high mass, WR22 most probably is still a hydrogen burning object. Therefore, the WN7 component is much closer to a main sequence O star with a "Wolf-Rayet clothing" than to the other members of the Wolf-Rayet family, which are rather highly evolved He-burning descendants of massive progenitors. [less ▲]

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See detailWolf-Rayet stars in the framework of stellar evolution.
Vreux, Jean-Marie ULg; Detal, Alain ULg; Fraipont-Caro, D. et al

Book (1996)

The following topics were dealt with: evolution of massive stars - theory; observational characteristics of Wolf-Rayet stars and related objects; evidences for evolutionary links - transition objects ... [more ▼]

The following topics were dealt with: evolution of massive stars - theory; observational characteristics of Wolf-Rayet stars and related objects; evidences for evolutionary links - transition objects; analysis of the observations - the models and their results; massive stars in starburst. [less ▲]

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See detailWR 134 line-profile variability : preliminary results of the 1994 campaign
Gosset, Eric ULg; Vreux, Jean-Marie ULg

in Vreux, J.-M.; Detal, Alain; Fraipont-Caro, Denise (Eds.) et al Wolf-Rayet stars in the framework of stellar evolution (1996)

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See detailThe Clover Leaf Quasar H1413+117: New Photometric Light Curves
Remy, M.; Gosset, Eric ULg; Hutsemekers, Damien ULg et al

in Kochanek, C. S.; Hewitt, Jacqueline N (Eds.) Astrophysical applications of gravitational lensing: proceedings of the 173rd Symposium of the International Astronomical Union (1996)

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See detailA new orbital solution for the WNL binary system WR12
Rauw, Grégor ULg; Vreux, Jean-Marie ULg; Gosset, Eric ULg et al

in Liege International Astrophysical Colloquia (1996)

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See detailA Deep Multicolour CCD Survey for Quasar Candidates with the OCA Schmidt Telescope
Moreau, O.; Gosset, Eric ULg; Royer, P. et al

in ASP Conf. Series (1995), 84

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See detailWR22 as a core hydrogen-burning Wolf-Rayet star
Rauw, Grégor ULg; Vreux, Jean-Marie ULg; Gosset, Eric ULg et al

in Stellar evolution: what should be done; 32nd Liege International Astrophysical Coll. (1995)

The analysis of an extensive sample of high resolution spectra of the Wolf-Rayet binary WR22 recently allowed us to determine a minimum mass of 72 M_solar for the WN7 star. With such a high mass, WR22 is ... [more ▼]

The analysis of an extensive sample of high resolution spectra of the Wolf-Rayet binary WR22 recently allowed us to determine a minimum mass of 72 M_solar for the WN7 star. With such a high mass, WR22 is expected to be a core H-Burning star which has just evolved from a progenitor of at least 90-110 M_solar. [less ▲]

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See detailA seven year campaign on WR 22
Rauw, Grégor ULg; Vreux, Jean-Marie ULg; Gosset, Eric ULg et al

in Wolf-Rayet Stars: Binaries; Colliding Winds; Evolution. International Astronomical Union. Symposium no. 163 (1995)

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See detailFurther results on the line-profile variability of WR 134
Gosset, Eric ULg; Vreux, Jean-Marie ULg; Andrillat, Y.

in Astrophysics & Space Science (1994, November 01), 221

We discuss a few conclusions previously derived from the analysis of the line-profile variability of the Wolf-Rayet star WR 134, some details are made more explicit. In addition, we present a new set of ... [more ▼]

We discuss a few conclusions previously derived from the analysis of the line-profile variability of the Wolf-Rayet star WR 134, some details are made more explicit. In addition, we present a new set of data and briefly comment on recent results deduced from its analysis. [less ▲]

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See detailA dusty nebula around the luminous blue variable candidate HD 168625
Hutsemekers, Damien ULg; van Drom, E.; Gosset, Eric ULg et al

in Astronomy and Astrophysics (1994), 290

On the basis of narrow-band visible and near-infrared imagery as well as high-resolution spectroscopy, we report the discovery of a new LBV-type nebula around the B supergiant HD 168625. We find that it ... [more ▼]

On the basis of narrow-band visible and near-infrared imagery as well as high-resolution spectroscopy, we report the discovery of a new LBV-type nebula around the B supergiant HD 168625. We find that it essentially consists of a dusty expanding shell from which seems to emerge a bipolar emission nebula, the whole embedded in a reflection nebulosity. The inner shell is stratified: the continuum emission arises beyond the ionized gas, and is possibly due to scattering of stellar light by large dust grains or to non-equilibrium dust emission. The unexpected presence of unidentified infrared emission bands (UIRs) in the spectrum of this object is also discussed. We finally report the non-detection of a comparable nebula around the nearby LBV HD 168607. [less ▲]

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See detailPhotometric monitoring of Wolf-Rayet stars: Strömgren uvby and narrow-band photometry
Gosset, Eric ULg; Rauw, Grégor ULg; Manfroid, Jean ULg et al

in NATO ASIC Proc. 436: The Impact of Long-Term Monitoring on Variable Star Research: Astrophysics (1994)

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