RESEARCH
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Discovery of a binary quasar at z = 1.76

E. Altamura, S. Brennan, A. Leśniewska, V. Pintėr, S. N. Reis, S. Geier, J. P. U. Fynbo

Abstract
We present the serendipitous discovery of a physical pair of quasars with estimated cosmological redshift z = 1.76. Long-slit spectroscopic observations of the candidate quasar GQ 1114+1549A were conducted with the OSIRIS instrument at the Gran Telescopio Canarias. The orientation of the slit allowed OSIRIS to also capture the spectrum of GQ 1114+1549B, an object with angular separation of ∆ θ = 8.76 arcsec from GQ 1114+1549A. Spectral analysis on the SiIV and CIV, CIII] emission lines confirmed the quasar nature of GQ 1114+1549A, as well as that of its newly discovered companion. The relative intensity for the emission lines and the shape of the continuum of the two objects were found to be significantly different, rendering the hypothesis of the system being a gravitationally lensed quasar highly unlikely. The projected physical distance between the two quasars was therefore estimated to be 75 kpc.

Keywords
quasars: general: emission lines; spectroscopy; quasars: individual: GQ 1114+1549; binary quasar

Contributions of the Astronomical Observatory Skalnatť Pleso
Volume 49, Number 3, Page 528
2019 December

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Instituto de Astrof√≠sica e Ci√™ncias do Espa√ßo Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia