Multi-object spectroscopy of the field surrounding PKS 2126-158: Discovery of a z=0.66 galaxy group

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 $z\sim 0.66$, 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.

Monthly Notices of the Royal Astronomical Society, in press. 10 pages, 8 figures

References in corpus (1)

• A catalogue of absorption-line systems in QSO spectra

Cited by in corpus (13)

• MUSE Analysis of Gas around Galaxies (MAGG) -- II: Metal-enriched halo gas around z~1 galaxies
• A Complete Census of Circumgalactic MgII at Redshift z<~ 0.5
• The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 < z < 1.5
• Metal-enriched halo gas across galaxy overdensities over the last 10 billion years
• MUSE Analysis of Gas around Galaxies (MAGG) -- IV: The gaseous environment of $z\sim$ 3-4 Lyman-alpha emitting galaxies
• MUSE-ALMA Halos V: Physical properties and environment of z < 1.4 HI quasar absorbers
• ALMACAL III: A combined ALMA and MUSE Survey for Neutral, Molecular, and Ionised Gas in an HI-Absorption-Selected System
• The Geometry of Cold, Metal-Enriched Gas Around Galaxies at $z\sim 1.2$
• The CGM at Cosmic Noon with KCWI: Outflows from a Star-forming Galaxy at z=2.071
• Characterizing circumgalactic gas around massive ellipticals at z~0.4 III. The galactic environment of a chemically-pristine Lyman limit absorber
• A Complex Multiphase DLA Associated with a Compact Group at z=2.431 Traces Accretion, Outflows, and Tidal Streams
• Disentangling the multi-phase circumgalactic medium shared between a dwarf and a massive star-forming galaxy at z~0.4
• Low Mass Group Environments have no Substantial Impact on the Circumgalactic Medium Metallicity