  Further investigation of the pair of quasars Q0107 - 025 A and BSurdej, Jean  ; ; Gosset, Eric et alin 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: 12 (1 ULg)A new very interesting pair of quasars - Q0107 - 025 A and BSurdej, Jean ; Swings, Jean-Pierre ; et alin 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 ▲] Detailed reference viewed: 12 (2 ULg)Short-term optical variability of HD 153919 = 4U1700-37; ; Surdej, Jean et alin Acta Astronomica (1979), 29(4), 481-503 Photometric observations of HD 153919 are presented, which indicate optical cyclic variations with an amplitude of up to 0.02 mag, and a strong dependence of the amplitude on the orbital plane. From power ... [more ▼] Photometric observations of HD 153919 are presented, which indicate optical cyclic variations with an amplitude of up to 0.02 mag, and a strong dependence of the amplitude on the orbital plane. From power spectrum analysis, a value of 99.9 min from the observations of van Paradijs et al. (1978) has been determined for the characteristic period. In addition, evidence suggests a secular decrease of the period with a rate of decrease of -0.03 per year. [less ▲] Detailed reference viewed: 11 (1 ULg) 4U 1700-37Surdej, Jean ; in IAU Astronomical Telegram N° 3290 (1978) IAUC 3290 available at Central Bureau for Astronomical Telegrams. Detailed reference viewed: 10 (1 ULg) |
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