References of "Surdej, Jean"
     in
Bookmark and Share    
Full Text
See detailDernière nouvelle: SN1987a brille toujours dans le Grand Nuage de Magellan
Surdej, Jean ULg

Article for general public (1987)

Detailed reference viewed: 11 (2 ULg)
Full Text
See detailL'explosion d'une supernova dans le Grand Nuage de Magellan
Surdej, Jean ULg

Article for general public (1987)

The author presents here an overview of the main results obtained so far about the bright supernova SN 1987A which exploded in the Large Magellanic Cloud.

Detailed reference viewed: 36 (4 ULg)
Full Text
Peer Reviewed
See detailGeometry of the mass-outflows around broad absorption line QSOs and formation of the complex Ly-alpha + N V line profile
Surdej, Jean ULg; Hutsemekers, Damien ULg

in Astronomy and Astrophysics (1987), 177

The possibility that the observed broad absorption line (BAL) profiles are formed in spherically symmetric atmospheres is investigated, and it is found that BAL and non-BAL QSOs form two distinct classes ... [more ▼]

The possibility that the observed broad absorption line (BAL) profiles are formed in spherically symmetric atmospheres is investigated, and it is found that BAL and non-BAL QSOs form two distinct classes of quasars. It is shown that the small residual intensity and large equivalent width noted for some absorption troughs may be reproduced by the resonance scattering of line photons across spherically symmetric BAL regions. N V emission strength is found to be higher in the spectrum of BAL QSOs than in that of non-BAL QSOs. Good agreement between theory and the observed attenuation of the Ly-alpha emission line, the observed enhancement of the N V emission strength, and the possible presence of a shoulderlike feature in the red wing of the N V emission profile is obtained. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailA new case of gravitational lensing
Surdej, Jean ULg; Magain, Pierre ULg; Swings, J.-P. et al

in Nature (1987), 329

The authors have begun a systematic search from ESO for gravitational lens systems in a selected sample of highly luminous quasars; M[SUB]V[/SUB] < -29.0. They give a brief description of their first ... [more ▼]

The authors have begun a systematic search from ESO for gravitational lens systems in a selected sample of highly luminous quasars; M[SUB]V[/SUB] < -29.0. They give a brief description of their first identified gravitational lens system UM673 = Q0142-100 = PHL3703. It consists of two images, A (m[SUB]R[/SUB] = 16.9) and B (m[SUB]R[/SUB] = 19.1), separated by 2.2 arc s at a redshift z[SUB]q[/SUB] = 2.719. The lensing galaxy (m[SUB]R[/SUB] â 19, Z[SUB]L[/SUB] â 0.49) has also been found. It lies very near the line connecting the two QSO images, â ¡0.8 arc s from the fainter one. A value M[SUB]0[/SUB] â 2.4×10[SUP]11[/SUP]M_sun; for the mass of the lensing galaxy and Deltat â 7 weeks for most likely travel-time difference between the two light paths to the QSO are found (assuming H[SUB]0[/SUB] = 75 km s[SUP]-1[/SUP]Mpc[SUP]-1[/SUP], q[SUB]0[/SUB] = 0). [less ▲]

Detailed reference viewed: 32 (6 ULg)
Full Text
Peer Reviewed
See detailL'objet le plus éloigné dans notre univers: Q0046-293
Surdej, Jean ULg

in Ciel et Terre (1987), 103

Detailed reference viewed: 13 (2 ULg)
Full Text
See detailThe high redshift of quasars
Surdej, Jean ULg

in Kleczek, J. (Ed.) Exercises in astronomy.. Revised and extended edition of "Practical work in elementary astronomy" by M. G. J. Minnaert. D. ReidelPublishing Co., Dordrecht, The Netherlands. 24+339 pp. Price Dfl. 140.00, US 64.00, £ 49.50 cloth; Dfl. 59.00, US 19.50, £ 18.00 paper (1987). ISBN 90-277-2409-1 cloth, ISBN 90-277-2423-7 paper. (1987)

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated ... [more ▼]

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated by the editor in collaboration with the contributing authors D. A. Allen, Z. Ceplechka, S. Ferraz Mello, K. J. Gordon, L. Houziaux, C. Jaschek, Z. Kopal, J. Manfroid, J. Palous, J. Podolský, G. R. Quast, J. Surdej, A. B. Underhill, J. M. Vreux, D. G. Wentzel.The exercises are organized in the following sections:A. The planetary system: 1. Space and time, instruments. 2. The motions of celestial bodies. 3. Planets and satellites.B. The stars: 1. The Sun. 2. Stars and nebulae. 3. Stellar systems. [less ▲]

Detailed reference viewed: 12 (2 ULg)
Full Text
See detailMirages caused by a gravitational lens
Surdej, Jean ULg

in Kleczek, J. (Ed.) Exercises in astronomy...Revised and extended edition of "Practical work in elementary astronomy" by M. G. J. Minnaert. D. ReidelPublishing Co., Dordrecht, The Netherlands. 24+339 pp. Price Dfl. 140.00, US 64.00, £ 49.50 cloth; Dfl. 59.00, US 19.50, £ 18.00 paper (1987). ISBN 90-277-2409-1 cloth, ISBN 90-277-2423-7 paper. (1987)

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated ... [more ▼]

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated by the editor in collaboration with the contributing authors D. A. Allen, Z. Ceplechka, S. Ferraz Mello, K. J. Gordon, L. Houziaux, C. Jaschek, Z. Kopal, J. Manfroid, J. Palous, J. Podolský, G. R. Quast, J. Surdej, A. B. Underhill, J. M. Vreux, D. G. Wentzel.The exercises are organized in the following sections:A. The planetary system: 1. Space and time, instruments. 2. The motions of celestial bodies. 3. Planets and satellites.B. The stars: 1. The Sun. 2. Stars and nebulae. 3. Stellar systems. [less ▲]

Detailed reference viewed: 16 (3 ULg)
See detailExercises in astronomy.
Kleczek, J.; Minnaert, M. G. J.; Allen, D. A. et al

in Exercises in astronomy.. J. Kleczek (Editor).Revised and extended edition of "Practical work in elementary astronomy" by M. G. J. Minnaert. D. ReidelPublishing Co., Dordrecht, The Netherlands. 24+339 pp. Price Dfl. 140.00, US 64.00, £ 49.50 cloth; Dfl. 59.00, US 19.50, £ 18.00 paper (1987). ISBN 90-277-2409-1 cloth, ISBN 90-277-2423-7 paper. (1987)

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated ... [more ▼]

This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated by the editor in collaboration with the contributing authors D. A. Allen, Z. Ceplechka, S. Ferraz Mello, K. J. Gordon, L. Houziaux, C. Jaschek, Z. Kopal, J. Manfroid, J. PalouÅ¡, J. Podolský, G. R. Quast, J. Surdej, A. B. Underhill, J. M. Vreux, D. G. Wentzel.The exercises are organized in the following sections:A. The planetary system: 1. Space and time, instruments. 2. The motions of celestial bodies. 3. Planets and satellites.B. The stars: 1. The Sun. 2. Stars and nebulae. 3. Stellar systems. [less ▲]

Detailed reference viewed: 157 (2 ULg)
Full Text
See detailOPTOPUS observations of Halley’s comet
Lund, G.; Surdej, Jean ULg

in The Messenger (1986), 43

The multiobject spectrograph OPTOPUS, for use at the 3.6-m ESO telescope with the CCD detector, is described, and preliminary results of spectra obtained in December 1985 of selected regions in the coma ... [more ▼]

The multiobject spectrograph OPTOPUS, for use at the 3.6-m ESO telescope with the CCD detector, is described, and preliminary results of spectra obtained in December 1985 of selected regions in the coma of Halley's comet are presented. The instrument's 54 separately cabled optical fibers, whose input ends are located in the focal plane by connectors plugged into drilled starplates, enable light to be guided from freely distributed points in a 33 arcmin zone of the Cassegrain focal plane, to a common slit. The spectra show the presence of a very faint continuum, due to the scattering of solar line photons in the inner region of the coma, on which is superimposed the bright emission bands of molecules such as CN, C2, C3, and NH2. The spectra also indicate that the brightness decrease of molecular bands as a function of the projected radial distance is not the same for different molecules. 3-3 (PDF) ESO [less ▲]

Detailed reference viewed: 19 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 30 (0 ULg)
Full Text
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 ▲]

Detailed reference viewed: 19 (7 ULg)
Full Text
See detailDetermination of mass-loss rates of planetary nebulae nuclei using the first order moment of P Cygni line profiles.
Hutsemekers, Damien ULg; Surdej, Jean ULg

in Comptes rendus sur les Journées de Strasbourg, 8ème réunion - Les Nébuleuses Planétaires (1986)

The authors conclude that the mass-loss rates of planetary nebulae nuclei derived by Cerruti-Sola, Perinotto (1985) have been systematically underestimated by one or nearly two orders of magnitude.

Detailed reference viewed: 23 (9 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 16 (2 ULg)
Full Text
Peer Reviewed
See detailPhotoelectric photometry of 22 Kalliope during the 1985 opposition and determination of its pole orientation - The 'magnitude-aspect' relations revisited
Surdej, Jean ULg; Pospieszalska-Surdej, Anna ULg; Michalowski, T. et al

in Astronomy and Astrophysics (1986), 170

Abstract image available at: http://esoads.eso.org/abs/1986A&A...170..167S

Detailed reference viewed: 14 (4 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailThe structure and spectral characteristics of the low-excitation planetary nebula HD 316248
Hutsemekers, Damien ULg; Surdej, Jean ULg

in Astronomy and Astrophysics (1985), 153

Analysis of two medium dispersion (39 Å/mm) optical spectra of the compact planetary nebula HD 316248 is reported here. When compared with observations collected in 1968 - 70, the authors' data obtained ... [more ▼]

Analysis of two medium dispersion (39 Å/mm) optical spectra of the compact planetary nebula HD 316248 is reported here. When compared with observations collected in 1968 - 70, the authors' data obtained in 1978 reveal a net increase of the [O III] lambdalambda4959, 5007 line intensities. Furthermore, despite showing unusual emission lines due to [Ti III], the low-excitation spectrum of HD 316248 presents striking similarities with that of a typical H II region. Direct plates taken through broad-band and interference filters at the prime focus of the ESO 3.6 m telescope clearly show that HD 316248 is an elongated (d â 4arcsec.4) and diffuse object as seen in the light of Halpha. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
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

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailCPD - 59 deg 2857 - A new red variable star
Gosset, Eric ULg; Hutsemekers, Damien ULg; Surdej, Jean ULg

in Publications of the Astronomical Society of the Pacific [=PASP] (1985), 97

Two (C3 and C4) of the four comparison stars monitored during the photometric study of the peculiar emission-line star GG Car (Gosset et al., 1984) have been found to be variable. Available photometric ... [more ▼]

Two (C3 and C4) of the four comparison stars monitored during the photometric study of the peculiar emission-line star GG Car (Gosset et al., 1984) have been found to be variable. Available photometric and spectroscopic data allow us to identify C4 with CPD - 59 deg 2857 and classify it as a late-type giant (M3-4 III) belonging to the red variable stars of the semiregular or irregular type. [less ▲]

Detailed reference viewed: 18 (2 ULg)
Full Text
Peer Reviewed
See detailAnalysis of P Cygni line profiles - Generalization of the nth order moment WN
Surdej, Jean ULg

in Astronomy and Astrophysics (1985), 152

The generalization of the nth order moment W[SUB]n[/SUB] of a P Cygni line profile leads to a new approach of deriving the various physical quantities which characterize the phenomenon of mass-loss around ... [more ▼]

The generalization of the nth order moment W[SUB]n[/SUB] of a P Cygni line profile leads to a new approach of deriving the various physical quantities which characterize the phenomenon of mass-loss around stars, quasars, etc. Adopting realistic expressions for the velocity and opacity distributions the author presents and discusses the results of calculations of the moments W[SUB]n[/SUB] in two types of different diagrams: the "log (W[SUB]n[/SUB])-log(W[SUB]n[/SUB][SUP]0[/SUP])" and "log(W[SUB]n[/SUB])-log (W[SUB]0[/SUB])" diagrams. The physical representation of the parameters W[SUB]n[/SUB][SUP]0[/SUP] is then given and the author tests and generalizes the validity of some of the linear relations W[SUB]n[/SUB] â W[SUB]n[/SUB][SUP]0[/SUP] for the case of slowly expanding optically thin atmospheres. [less ▲]

Detailed reference viewed: 47 (1 ULg)
Full Text
Peer Reviewed
See detailDetermination of the pole orientation of an asteroid - The amplitude-aspect relation revisited
Pospieszalska-Surdej, Anna ULg; Surdej, Jean ULg

in Astronomy and Astrophysics (1985), 149

Near the opposition of a minor planet the geometrical approximation essentially constitutes a good representation of the Hapke-Irvine relation for describing the scattering properties of a surface layer ... [more ▼]

Near the opposition of a minor planet the geometrical approximation essentially constitutes a good representation of the Hapke-Irvine relation for describing the scattering properties of a surface layer, and the authors show that the normalized light curve of a three-axes ellipsoid model reduces to a straight line whose slope depends only on the aspect angle A and on the semi-axes ratios a/b, b/c of the ellipsoid. A set of non-linear equations is then solved by a least squares method in order to derive the four unknown parameters lambda[SUB]0[/SUB], beta[SUB]0[/SUB] (ecliptic coordinates of the pole) and a/b, b/c. The authors have applied this technique to published observations of two asteroids: For (624) Hektor two possible solutions are found; and for the case of (44) Nysa, they show that additional observations are needed in order to derive a self-consistent pole orientation. [less ▲]

Detailed reference viewed: 51 (8 ULg)