Multi-object spectroscopy of the field surrounding PKS 2126−158: discovery of a z= 0.66 galaxy group |
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| Authors: | Matthew T Whiting Rachel L Webster Paul J Francis |
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| Institution: | School of Physics, University of New South Wales, Sydney, NSW 2052, Australia;Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia;School of Physics, University of Melbourne, VIC 3010, Australia;Research School of Astronomy and Astrophysics, Australian National University, ACT 0200, Australia |
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| Abstract: | The high-redshift radio-loud quasar PKS 2126?158 is found to have a large number of red galaxies in close apparent proximity. We use the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to obtain optical spectra for a large fraction of these sources. We show that there is a group of galaxies at z ～ 0.66 , coincident with a metal-line absorption system seen in the quasar's optical spectrum. The multiplexing capabilities of GMOS also allow us to measure redshifts of many foreground galaxies in the field surrounding the quasar.
The galaxy group has five confirmed members, and a further four fainter galaxies are possibly associated. All confirmed members exhibit early-type galaxy spectra, a rare situation for a Mg ii absorbing system. We discuss the relationship of this group to the absorbing gas, and the possibility of gravitational lensing of the quasar due to the intervening galaxies. |
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| Keywords: | gravitational lensing galaxies: general quasars: absorption lines quasars: individual: PKS 2126?158 |
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