References of "Swings, Jean-Pierre"
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See detailProfiles of a Key Programme: Gravitational Lensing
Surdej, Jean ULg; Arnaud, J.; Borgeest, U. et al

in The Messenger (1989), 55

Prior to Professor van der Laan's enquiry, in the March 1988 issue of the Messenger, on the general interest among astronomers from the European community to possibly participate in Key Programmes (KPs ... [more ▼]

Prior to Professor van der Laan's enquiry, in the March 1988 issue of the Messenger, on the general interest among astronomers from the European community to possibly participate in Key Programmes (KPs) at the European 80uthern Observatory, at least three distinct groups (including more than half of the above authors) were already involved in the study of "gravitational lensing" effects (see box on pages 10-11). Observations were being performed with the help of various telescopes on La 8illa as weil as at other observatories (VLA, CFHT, Palomar, Kitt Peak, etc.). [less ▲]

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See detailStatistical tests applied to the spatial distribution of quasars in several fields.
Gosset, Eric ULg; Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Osmer, P. S.; Porter, A. C.; Green, R. F. (Eds.) et al Optical surveys for quasars (1988)

The authors discuss the application of different statistical tests to the study of the spatial distribution of quasars. Applications to data sets of optically selected quasars lead to the detection of a ... [more ▼]

The authors discuss the application of different statistical tests to the study of the spatial distribution of quasars. Applications to data sets of optically selected quasars lead to the detection of a clustering at a typical scale of 10 arcmin. Furthermore, the spatial distribution of quasars in a field around NGC 450 shows a deviation from randomness, towards clustering, at a scale of 10 h[SUP]-1[/SUP]Mpc. [less ▲]

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See detailSurveys of Ultraviolet Excess Quasar Candidates in Three Large Fields
Swings, Jean-Pierre ULg; Surdej, Jean ULg; Gosset, Eric ULg

in Osmer, Patric S. (Ed.) Astron. Soc. of the Pac. Conf. Series: Optical Surveys for Quasars (1988)

A general description is given of the surveys performed in the fields around NGC 450 and NGC 520, and in the ESO field No. 300 with the aim of detecting ultraviolet excess quasar candidates.

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See detailPreliminary results from a search for gravitational lensing within a sample of highly luminous quasars
Surdej, Jean ULg; Magain, Pierre ULg; Swings, Jean-Pierre ULg et al

in Balkowski, C.; Gordon, S. (Eds.) Proceedings to the First D.A.E.C. workshop on "Large Scale Structures" (1988)

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See detailThe ultraviolet spectrum of the peculiar emission-line star GG Carinae
Brandi, E.; Gosset, Eric ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics (1987), 175

This paper presents the first study of the properties of the peculiar emission-line star GG Carinae in the ultraviolet wavelength domain. From IUE high resolution spectra, the authors investigate the ... [more ▼]

This paper presents the first study of the properties of the peculiar emission-line star GG Carinae in the ultraviolet wavelength domain. From IUE high resolution spectra, the authors investigate the behaviour of different velocities. From IUE low resolution data, they propose a value of the B-V excess of E[SUB]B-V[/SUB] = 0.52±0.04 (2σ). The continuum of GG Car from the UV to the visible is rather well represented by the theoretical flux of a T[SUB]eff[/SUB] = 18,000K Kurucz standard model atmosphere. The authors investigate also the ultraviolet light curve, which is essentially similar to the one observed in the visible (Gosset et al., 1984, 1985). [less ▲]

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See detailIs There an Alignment of Quasars Near NGC 520?
Gosset, Eric ULg; Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Hewitt, Adelaide; Burbidge, Geoffrey; Fang, Li Zhi (Eds.) IAU Symposium, No. 124 "Observational Cosmology" (1987)

Three statistical tests applied to 65 UV excess objects in the field of NGC 520 lead to no detection of any significant alignment.

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See detailSpectroscopy of the QSSOs Q0118-031 A, B, C
Robertson, J. G.; Shaver, P. A.; Surdej, Jean ULg et al

in Monthly Notices of the Royal Astronomical Society (1986), 219

Optical spectroscopy of the three quasars Q0118-031A, B, C is presented. These objects which have emission redshifts of 12.445, 2.112 and 1.165 respectively, form a triplet on the plane of the sky with ... [more ▼]

Optical spectroscopy of the three quasars Q0118-031A, B, C is presented. These objects which have emission redshifts of 12.445, 2.112 and 1.165 respectively, form a triplet on the plane of the sky with separations of 4.8, 4.9 and 0.4 arcmins. Low dispersion spectra were obtained for all three objects, and intermediate dispersion spectra instrumental in the search for absorption lines were obtained for objects B and C. QSO B was found to have a rich absorption line spectrum, with definite systems at z(abs) 1.4648 and 2.0192. No absorption lines were found in the given spectrum for QSO C. Estimated column densities and velocity dispersions are given for the absorption systems in QSO B, and it is noted that the one at z(abs) = 1.4648 differs by only 2400 + or - 250 km/s from the emission redshift of QSO A. Since the spatial separation was predicted to be 1.2 Mpc, this absorption system may be due to material related to a galaxy in a cluster which also contains QSO A. It is suggested that this associated absorption is connected to the fact that quasars are located in regions of higher than average matter density. [less ▲]

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See detailUltraviolet Excess Quasar Candidates in Large Fields: a Status Report Concerning the NGC 450 Area
Gosset, Eric ULg; Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Swarup, G.; Kapahi, V. K. (Eds.) Quasars (1986)

New results are presented based on several statistical analyses of a 25 square degree field around NGC 450. They include the detection of a clustering on a small scale (≅10 arcminutes) and possible large ... [more ▼]

New results are presented based on several statistical analyses of a 25 square degree field around NGC 450. They include the detection of a clustering on a small scale (≅10 arcminutes) and possible large scale inhomogeneities. [less ▲]

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See detailFurther investigation of the pair of quasars Q0107 - 025 A and B
Surdej, Jean ULg; Arp, H.; Gosset, Eric ULg et al

in Astronomy and Astrophysics (1986), 161

Low and intermediate dispersion spectroscopy of Q0107 - 025 A and B obtained at ESO, AAT, and MMT provide evidence for spectral differences between these two quasars. A redshift difference of 0.004 is ... [more ▼]

Low and intermediate dispersion spectroscopy of Q0107 - 025 A and B obtained at ESO, AAT, and MMT provide evidence for spectral differences between these two quasars. A redshift difference of 0.004 is found between the two objects, and forbidden emission lines due to O II (3727 A), Ne III (1815), and possibly Ne V (3426 A), are seen in the spectrum of Q0107 - 025 A, while only the forbidden Ne III line at 1815 A is possibly detected in the spectdrum of Q0107 - 025 B. No narrow absorption lines could be detected in the 3252 - 5616 A spectral range of the intermediate resolution data of either quasar, and the spectrum of quasar B is found to be steeper in the blue that of the quasar A. The possible presence of a highly redshifted cluster of galaxies in the field of these quasars is suggested by CCD photometry. [less ▲]

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See detailRadial velocities along the light curve of the peculiar emission-line star GG Carinae
Gosset, Eric ULg; Hutsemekers, Damien ULg; Swings, Jean-Pierre ULg et al

in Astronomy and Astrophysics (1985), 153

Measurements of the radial velocities of several emission and absorption lines in a large series of high dispersion spectra of the peculiar emission-line object GG Carinae are combined with the ... [more ▼]

Measurements of the radial velocities of several emission and absorption lines in a large series of high dispersion spectra of the peculiar emission-line object GG Carinae are combined with the photometric data described by Gosset et al. (1984) in an attempt to derive constraints on a qualitative physical model of this peculiar, and most probably binary, object. Previously unreported spectral features are the double absorption components of the Balmer lines and the He I absorption lines appearing around phase phi = 0.45 of the 31.02 day period deduced from the radial velocity curve. [less ▲]

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See detailQuasar Candidates in a Large Field Centered around NGC450 and the Discovery of a New Very Interesting Pair of Quasars
Swings, Jean-Pierre ULg; Surdej, Jean ULg; Henry, A. et al

in Revista Mexicana de Astronomia y Astrofisica, vol. 10 (1985), 10

Abstract image available at: http://esoads.eso.org/abs/1985RMxAA..10...91S

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See detailTwo quasars seen near the spiral galaxy NGC 470
Arp, H.; Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics (1984), 138

The discovery of two quasars with 16arcsec separation from each other on the sky and within 95arcsec of the nucleus of the spiral galaxy NGC 470 is reported. The quasars were discovered in a search for ... [more ▼]

The discovery of two quasars with 16arcsec separation from each other on the sky and within 95arcsec of the nucleus of the spiral galaxy NGC 470 is reported. The quasars were discovered in a search for ultraviolet-excess objects in four overlapping fields of about 25 square degrees each. Preliminary spectroscopy of the quasars yields z = 1.875 (mv = 19.9 mag) and z = 1.533 (mv = 18.2 mag). [less ▲]

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See detailLes quasars.
Henry, A.; Swings, Jean-Pierre ULg; Gosset, Eric ULg

in Ciel (Le) (1984), 46

Not Available

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See detailMore on the reflection nebula surrounding HD 87643 and the non-uniform atmosphere of the central star
Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics (1983), 117

Different equivalent widths and line displacements of Hbeta and Fe II are observed in spectra of two condensations located within the reflection nebula surrounding HD 87643: they indicate important ... [more ▼]

Different equivalent widths and line displacements of Hbeta and Fe II are observed in spectra of two condensations located within the reflection nebula surrounding HD 87643: they indicate important relative motions (Deltav â ¡ 150 km s[SUP]-1[/SUP]) between various parts of the nebulosity and demonstrate that the stellar atmosphere in which the lines are formed is not isotropic and/or not homogeneous. The spectrum of another reflection nebula situated in the vicinity of HD 87643 is also briefly described. [less ▲]

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See detailA new very interesting pair of quasars - Q0107 - 025 A and B
Surdej, Jean ULg; Swings, Jean-Pierre ULg; Henry, A. et al

in 24th Liege International Astrophysical Colloquium: "Quasars and gravitational lenses" (1983)

A search for ultraviolet-excess objects in a field centered around NGC 450 has revealed the presence of two quasar-candidates (18.2 and 17.4 mag) fairly near one another (separation of 77 arcsec ... [more ▼]

A search for ultraviolet-excess objects in a field centered around NGC 450 has revealed the presence of two quasar-candidates (18.2 and 17.4 mag) fairly near one another (separation of 77 arcsec). Preliminary spectroscopy with the Palomar 5 m telescope shows that these objects are indeed two quasars (Q0107 - 025 A and B) having very similar spectra and redshifts (of about 0.96), suggesting a new possible case of twin quasars or of a gravitational lens. Although the analysis (to be published elsewhere) of additional spectroscopic data collected with the ESO 3.6 m telescope rather favors the first interpretation, higher resolution data are still necessary before rejecting definitely the second possibility. Deep multi-color CCD frames obtained with the Danish 1.5 m telescope clearly show that a group (or cluster) of faint galaxies is detected in the vicinity of the two quasars. [less ▲]

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See detailA Survey of Ultraviolet Excess Quasar Candidates in a Large Field around NGC450
Swings, Jean-Pierre ULg; Arp, H.; Surdej, Jean ULg et al

in LIAC Colloq. 24: Quasars and Gravitational Lenses (1983)

Preliminary results of a search for QSO candidates in a 25 square degree field around NGC 450 are presented.

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See detailSpectroscopic observations of thirteen optically-selected QSOs in a large field centred around NGC 5334
Surdej, Jean ULg; Swings, Jean-Pierre ULg; Arp, H. C. et al

in Astronomy and Astrophysics (1982), 114

A large field (approximately 25 sq deg) around NGC 5334 was searched for QSO candidates with ultraviolet-excess, in order to investigate the space density, distribution, and luminosity of quasars near as ... [more ▼]

A large field (approximately 25 sq deg) around NGC 5334 was searched for QSO candidates with ultraviolet-excess, in order to investigate the space density, distribution, and luminosity of quasars near as well as far from bright galaxies. Spectroscopic data obtained with the European Southern Observatory 3.6 m telescope are presented for 13 quasars identified within a sample of 23 observed candidates. As expected, the redshift of these optically selected quasars was found to fall in the range 0.23-2.08, with only one exception. Two, and possibly three, of the quasars of the largest redshift show absorption lines, while the remaining 10 faint blue objects display zero-redshift stellar spectra. [less ▲]

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See detailSpectral variations and evidence for edge and/or line locking mechanism/s/ in the low-excitation planetary nebula HD 138403
Surdej, Anna ULg; Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics (1982), 105

Spectral variations detected within the last three decades for He II 4686 A, forbidden lines O III and other high excitation lines in the low-excitation planetary nebula HD 138403, are shown to suggest ... [more ▼]

Spectral variations detected within the last three decades for He II 4686 A, forbidden lines O III and other high excitation lines in the low-excitation planetary nebula HD 138403, are shown to suggest appreciable activity in the deep atmospheric layers of the nucleus, and an increase of the excitation of the nebula. The spectrum of the nebula is found to be unusual due to the presence of red and blue emission satellites around the central Balmer (H-beta - H9) lines and forbidden lines O II 3726, 3729 A, with a velocity separation equal to plus 122 and minus 126 km/s, respectively. These features are interpreted as evidence for mass outflow from the central object via the selective radiation process of edge and/or line locking mechanisms. [less ▲]

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See detailFurther spectroscopic observations of 25 quasi-stellar objects
Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1981), 46

Spectroscopic observations are reported for 25 quasars suspected of having line profiles which are indicative of mass outflow from the central quasar. The quasars were selected on the basis of optical ... [more ▼]

Spectroscopic observations are reported for 25 quasars suspected of having line profiles which are indicative of mass outflow from the central quasar. The quasars were selected on the basis of optical variability and/or the presence of P Cygni spectral profiles, and large emission redshift, and observed on widened spectrograms obtained at the Cassegrain focus of the ESO 3.6-m telescope at La Silla during December 1977 and July 1978. Observations confirm the previously detected emission and absorption redshifts for most of the quasars, and reveal previously undetected lines and absorption redshifts in a few cases. [less ▲]

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See detailDecelerated flows of matter around the quasars PHL 5200 and RS 23
Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics (1981), 96

Line profile calculations are performed within the framework of the Sobolev approximation in order to simulate the P Cygni-like profiles observed for the resonance doublets of C IV and Si IV in the ... [more ▼]

Line profile calculations are performed within the framework of the Sobolev approximation in order to simulate the P Cygni-like profiles observed for the resonance doublets of C IV and Si IV in the spectrum of the quasar PHL 5200 and of C IV in that of RS 23. Taking into account the structure of the resonance doublets and the nonlocal transfer of line photons in an outward-decelerating envelope, it is shown that good agreement between the theory and the observations is achieved for symmetrically spherical outward-flows decelerated in the gravitational field of the central quasars. [less ▲]

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