Large-Scale Velocity Structures in the Horologium-Reticulum Supercluster

Abstract

We present 547 optical redshifts obtained for galaxies in the region of the HorologiumReticulum Supercluster (HRS) using the 6dF multi-fiber spectrograph on the UK Schmidt Telescope at the Anglo Australian Observatory. The HRS covers an area of more than 12 × 12 on the sky centered at approximately α = 0319, δ = −5002. Our 6dF observations concentrate upon the inter-cluster regions of the HRS, from which we describe four primary results. First, the HRS spans at least the redshift range from 17,000 to 22,500 km s. Second, the overdensity of galaxies in the inter-cluster regions of the HRS in this redshift range is estimated to be 2.4, or δρ/ρ̄ ∼ 1.4. Third, we find a systematic trend of increasing redshift along a Southeast-Northwest (SE−NW) spatial axis in the HRS, in that the mean redshift of HRS members increases by more than 1500 km s from SE to NW over a 12 region. Fourth, the HRS is bi-modal in redshift with a separation of ∼2500 km s (35 Mpc) between the higher and lower redshift peaks. This fact is particularly evident if the above spatial-redshift trend is fitted and removed. In short, the HRS appears to consist of two components in redshift space, each one exhibiting a similar systematic spatial-redshift trend along a SE−NW axis. Lastly, we compare these results from the HRS with the Shapley supercluster and find similar properties and large-scale features. Subject headings: galaxies: clusters: general, large-scale structure

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Cite this paper

@inproceedings{Fleenor2005LargeScaleVS, title={Large-Scale Velocity Structures in the Horologium-Reticulum Supercluster}, author={Matthew Fleenor and James A. Rose and Wayne A. Christiansen and Richard W . Hunstead and Melanie Johnston-Hollitt and Michael Drinkwater and William Saunders}, year={2005} }