Publication details
THE MAJOR CLUSTER MERGER IN ABELL 2034 AS SEEN BY XRISM: STRONG TURBULENCE AND SPECTRAL ANOMALIES?
| Authors | |
|---|---|
| Year of publication | 2026 |
| Type | Peer-reviewed scientific article |
| Magazine / Source | Open Journal of Astrophysics |
| MU Faculty or unit | |
| Citation | |
| web | https://astro.theoj.org/article/168514-the-major-cluster-merger-in-abell-2034-as-seen-by-xrism-strong-turbulence-and-spectral-anomalies |
| Doi | https://doi.org/10.33232/001c.168514 |
| Keywords | Galaxy clusters; High energy astrophysics; Intracluster medium; Spectroscopy |
| Description | XRISM observations to date have shown that gas kinetic pressures in the intracluster medium (ICM) tend towards the low end of predictions from cosmological simulations. Here, we present a XRISM observation of the merging cluster Abell 2034, which exhibits the broadest emission lines yet observed in a galaxy cluster. We measure a velocity dispersion of ~470 km/s, corresponding to a kinetic pressure fraction of ~15%. This places A2034 at or above the high end of the theoretical predictions for similar-mass clusters. This large velocity dispersion may reflect Mach ~0.5 turbulence in the ICM and/or result from a core disruption driven by the ongoing head-on merger. We also detect a ~380 km/s gas bulk velocity gradient along the merger axis with an opposite sign to the galaxy velocity gradient, indicating a decoupling of the cluster galaxies (and dark matter) from the ICM. Finally, we report tentative evidence of several spectral anomalies, including a suppressed Fe He?-z line, an enhanced Fe Ly?-2 line, and a potential absorption feature at ~8.7 keV. The first two features may be explained by the combination of a multi-component ICM and a non-equilibrium ionization state in the wake of a merger shock. Deeper XRISM observations of this cluster are required to confirm these features. This work highlights the importance of kinematic measurements across a large sample of merging clusters as well as the need for deep XRISM observations to unveil more exotic physics in the ICM. |
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