PSZ2 G282.28+49.94, a recently discovered analogue of the famous Bullet Cluster

¹ INAF, IASF-Milano, via A. Corti 12, 20133 Milano, Italy
² Fundación Galileo Galilei – INAF (Telescopio Nazionale Galileo), Rambla José Ana Fernández Perez 7, 38712 Breña Baja (La Palma), Canary Islands, Spain
³ Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38205 La Laguna (Tenerife), Canary Islands, Spain
⁴ Departamento de Astrofísica, Univ. de La Laguna, Av. del Astrofísico Francisco Sánchez s/n, 38205 La Laguna (Tenerife), Canary Islands, Spain
⁵ Dipartimento di Fisica dell’Università degli Studi di Trieste – Sezione di Astronomia, via Tiepolo 11, 34143 Trieste, Italy
⁶ INAF – Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy
⁷ Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano, Italy
⁸ DiSAT, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy
⁹ Space Telescope Science Institute, Baltimore, MD, USA
¹⁰ INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
¹¹ U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Code 7213, Washington, DC 20375, USA
¹² Lorentz Institute, Leiden University, Niels Bohrweg 2, Leiden, N2333 CA, The Netherlands
¹³ Center for Astrophysical Sciences, Department of Physics and Astronomy, The Johns Hopkins University, 3400 N Charles St., Baltimore, MD 21218, USA
¹⁴ INAF – Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
¹⁵ Department of Physics, Ben-Gurion University of the Negev, PO Box 653, Be’er-Sheva 84105, Israel

Received: 22 April 2024
Accepted: 13 July 2024

Abstract

We present a detailed study of the gas and galaxy properties of the cluster PSZ2 G282.28+49.94 detected in the Planck all-sky survey. The intracluster medium (ICM) of this object at z=0.56 exhibits a cometary-like shape. Combining Chandra and TNG observations, we characterised the spatially resolved thermodynamical properties of the gas and the spatial and velocity distribution of 73 galaxy members. The cluster structure is quite complex with an elongated core region containing the two brightest cluster galaxies and one dense group to the south-east. Since there is no velocity difference between the core and the south-east group, we suggest the presence of a merger along the plane of the sky. This structure is related to complex X-ray and radio features, and thus the merger has likely been caught during the post-merger phase. Comparing the distribution of the ICM and of member galaxies, we find a large offset of ~350 kpc between the position of the X-ray peak and the centre of a concentration of galaxies, preceding it in the likely direction of motion. This configuration is similar to the famous Bullet Cluster, leading us to dub PSZ2 G282.28+49.94 the ‘Planck bullet’, and represents an ideal situation to provide astrophysical constraints to the self-interaction cross-section (σ/m) of dark matter particles. These results illustrate the power of a multi-wavelength approach to probe the merging scenario of such complex and distant systems.