A 'MeerKAT-meets-LOFAR' study of the complex multi-component (mini-)halo in the extreme sloshing cluster Abell 2142
Astronomy & Astrophysics(2024)
摘要
Clusters of galaxies are turbulent environments, whether merging systems with
a turbulent intracluster medium (ICM) or relaxed systems sloshing within the
potential well. In many such clusters, diffuse radio sources associated with
the ICM are found: radio haloes and mini-haloes. Abell 2142 is a rich cluster
undergoing extreme core sloshing, generating four cold fronts and a complex
multi-component radio halo. Recent work revealed three halo components which
span 2.4 Mpc. Particle acceleration on such scales is poorly understood, and
requires high-quality multi-frequency data to understand. We use new deep
MeerKAT L-band (1283 MHz) observations, combined with LOFAR HBA (143 MHz) data
and X-ray data from XMM-Newton and Chandra to study the spectrum of the halo
and the connection between the thermal and non-thermal components of the ICM.
We detect the third halo component for the first time at 1283 MHz and confirm
its ultra-steep spectrum nature, recovering α_ H3, total = -1.68 ±
0.10. All components follow power-law spectra which steepen toward the cluster
outskirts. We profile the halo along three directions, finding evidence of
asymmetry and spectral steepening perpendicular to the main axis of the
cluster. Our thermal/non-thermal investigation shows sub-linear correlations
that are steeper at 1283 MHz than 143 MHz, and we find different connections in
different components of the halo. We find both a moderate anti-correlation (H1,
the core) and positive correlation (H2, the ridge) between radio spectral index
and X-ray temperature. Our results are broadly consistent with an
interpretation of inhomogeneous turbulent (re-)acceleration. However, the
anti-correlation between radio spectral index and X- ray temperature in the
cluster core is challenging to explain; the presence of three cold fronts and a
generally lower temperature may provide the foundations of an explanation.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要