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See detailA spectroscopic study of UM 673 A and B - On the size of Lyman-alpha clouds
Smette, A.; Surdej, Jean ULg; Shaver, P. A. et al

in Astrophysical Journal (1992), 389

The Ly-alpha forest spectra obtained for the A and B images of the gravitationally lensed high-redshift quasar UM 673 are investigated, and higher resolution data of the brightest (A) image are presented ... [more ▼]

The Ly-alpha forest spectra obtained for the A and B images of the gravitationally lensed high-redshift quasar UM 673 are investigated, and higher resolution data of the brightest (A) image are presented. In the 2-A resolution spectra, all the absorption lines detected at 5 sigma in the spectrum of the fainter B image are present in the A image, but two anticoincidences, i.e., two lines in A which do not have a counterpart in B at more than a 3-sigma confidence level, are detected. Given the fact that corresponding Ly-alpha lines in the spectra of A and B have their equivalent widths well correlated, this proves that both light beams actually cross the same clouds. Most of the velocity differences between corresponding lines are compatible with 0 km/s within the error bars, with a standard deviation of 17 km/s. For the two major heavy-element systems detected in the spectrum of UM 673, no significant difference between the corresponding lines in the two spectra are found. [less ▲]

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See detailA Spectroscopic Study of UM673 A &B: on the size of Lyman- alpha Clouds
Smette, A.; Surdej, Jean ULg; Shaver, P. A. et al

in Quasar Absorption Lines, Proceedings of the ESO Mini-Workshop (1991)

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See detailPreliminary analysis of high-resolution spectra for UM 673 A & B
Smette, A.; Surdej, Jean ULg; Shaver, P. A. et al

in Mellier, Y.; Fort, B.; Soucail, G. (Eds.) Gravitational Lensing (1990)

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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 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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