Inquiring into the nature of the Abell 2667 brightest cluster galaxy: physical properties from MUSE.

Based on HST and MUSE data, we probe the stellar and gas properties (i.e. kinematics, stellar mass, star formation rate) of the radio-loud brightest cluster galaxy (BCG) located at the centre of the X-ray-luminous cool-core cluster Abell 2667 (z  = 0.2343). The bi-dimensional modelling of the BCG surface brightness profile reveals the presence of a complex system of substructures extending all around the galaxy. Clumps of different size and shape plunged into a more diffuse component constitute these substructures, whose intense 'blue' optical colour hints at the presence of a young stellar population. Our results depict the BCG as a massive (M _⋆ ≃ 1.38 × 10¹¹ M_⊙) dispersion-supported spheroid (Δ v _⋆ ≤ 150 km s⁻¹, σ₀ ∼ 216 km s⁻¹) hosting an active supermassive black hole (M _SMBH ≃ 3.8 × 10⁹ M_⊙) whose optical features are typical of low-ionization nuclear emission line regions. Although the velocity pattern of the stars in the BCG is irregular, the stellar kinematics in the regions of the clumps show a positive velocity of ∼100 km s⁻¹, similarly to the gas component. An analysis of the mechanism giving rise to the observed lines in the clumps through empirical diagnostic diagrams points out that the emission is composite , suggesting contribution from both star formation and an active galactic nucleus. We conclude our analysis describing how scenarios of both chaotic cold accretion and merging with a gas-rich disc galaxy can efficaciously explain the phenomena the BCG is undergoing. [ABSTRACT FROM AUTHOR]