Cooling rate and turbulence in the intracluster medium of the cool-core cluster Abell 2667

¹ INAF-Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
² Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Via Sansone, 1, 50019 Sesto Fiorentino, Firenze, Italy
³ INAF – IASF Palermo, Via Ugo La Malfa 153, 80146 Palermo, Italy
⁴ Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, 41125 Modena, Italy
⁵ INAF-IASF Milano, Via A. Corti 12, I-20133 Milano, Italy
⁶ Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748 Garching, Germany
⁷ Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206, China
⁸ Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122 Ferrara, Italy
⁹ University of Leiden, Rapenburg 70, 2311 EZ Leiden, The Netherlands
¹⁰ Kapteyn Astronomical Institute, University of Groningen, PO Box 800 9700 AV Groningen, The Netherlands
¹¹ Department of Physics and Astronomy, Università degli Studi di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, Italy
¹² INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy

^⋆ Corresponding author; marika.lepore@inaf.it

Received: 27 September 2024
Accepted: 29 December 2024

Abstract

Context. We present a detailed analysis of the thermal X-ray emission from the intracluster medium in the cool-core galaxy cluster Abell 2667 at z = 0.23.

Aims. Our main goal is to detect low-temperature (< 2 keV) X-ray emitting gas associated with a potential cooling flow connecting the hot intracluster medium reservoir to the cold gas phase responsible for star formation and supermassive black hole feeding.

Methods. We combined new deep XMM-Newton EPIC and RGS data, along with archival Chandra data, and performed a spectral analysis of the emission from the core region.

Results. We find 1σ upper limits on the fraction of gas cooling equal to ∼40 M_⊙ yr⁻¹ and ∼50−60 M_⊙ yr⁻¹, in the temperature ranges of 0.5−1 keV and 1−2 keV, respectively. We do not identify OVII, FeXXI-FeXXII, and FeXVII recombination and resonant emission lines in our RGS spectra, implying that the fraction of gas cooling below 1 keV is limited to a few tens of solar masses per year at maximum. We do detect several lines (particularly SiXIV, MgXII, FeXXIII/FeXXIV, NeX, OVIIIα) from which we are able to estimate the turbulent broadening. We obtain a 1σ upper limit of ∼320 km/s, which is much higher than the one found in other cool-core clusters such as Abell 1835, suggesting the presence of some mechanisms that boost significant turbulence in the atmosphere of Abell 2667. Imaging analysis of Chandra data suggests the presence of a cold front possibly associated with sloshing or with intracluster medium cavities. However, current data do not allow us to clearly identify the dominant physical mechanism responsible for turbulence.

Conclusions. These findings show that Abell 2667 is not different from other, low-redshift, cool-core clusters, with only upper limits on the mass deposition rate associated with possible isobaric cooling flows. Despite the lack of clear signatures of recent feedback events, the large upper limit on the turbulent velocity leaves room for significant heating of the intracluster medium, which may quench cooling in the cool core for an extended period, albeit also driving local intracluster medium fluctuations that will contribute to the next cycle of condensation rain.