Studying the merging cluster Abell 3266 with eROSITA

¹ Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching, Germany
e-mail: jsanders@mpe.mpg.de
² Universitäts-Sternwarte München, Ludwig-Maximilians-Universität München, Scheinerstr. 1, 81679 Munich, Germany
³ INAF – Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy
⁴ IFPU – Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
⁵ Hamburger Sternwarte, University of Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
⁶ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
⁷ Center for Astrophysics, Harvard & Smithsonian, 60 Garden St., MS-67, Cambridge, MA 02138, USA

Received: 9 June 2021
Accepted: 24 September 2021

Abstract

Abell 3266 is one of the X-ray brightest galaxy clusters in the sky and is a well-known merging system. Using the ability of the eROSITA telescope onboard SRG (Spectrum Röntgen Gamma) to observe a wide field with a single pointing, we analysed a new observation of the cluster out to a radius of R₂₀₀. The X-ray images highlight sub-structures present in the cluster, including the north-east-south-west merger seen in previous ASCA, Chandra, and XMM-Newton data, a merging group towards the north-west, and filamentary structures between the core and one or more groups towards the west. We compute spatially resolved spectroscopic maps of the thermodynamic properties of the cluster, including the metallicity. The merging subclusters are seen as low entropy material within the cluster. The filamentary structures could be the rims of a powerful outburst of an active galactic nucleus, or most likely material stripped from the western group(s) as they passed through the cluster core. Seen in two directions is a pressure jump at a radius of 1.1 Mpc, which is consistent with a shock with a Mach number of ~1.5–1.7. The eROSITA data confirm that the cluster is not a simple merging system, but it is made up of several subclusters which are merging or will shortly merge. We computed a hydrostatic mass from the eROSITA data, finding good agreement with a previous XMM-Newton result. With this pointing we detect several extended sources, where we find secure associations between z = 0.36–1.0 for seven of them, that is background galaxy groups and clusters, highlighting the power of eROSITA to find such systems.