PSZ2 G181.06+48.47 II: radio analysis of a low-mass cluster with exceptionally-distant radio relics

Fuente: arXiv
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Autori principali: Rajpurohit, Kamlesh, Stroe, Andra, O'Sullivan, Ewan, Ahn, Eunmo, Lee, Wonki, Cho, Hyejeon, Jee, M. James, van Weeren, Reinout, Lovisari, Lorenzo, Finner, Kyle, Simionescu, Aurora, Forman, William, Shimwell, Timothy, Jones, Christine, Zhu, Zhenlin, Randall, Scott
Natura: Preprint
Pubblicazione: 2025
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author Rajpurohit, Kamlesh
Stroe, Andra
O'Sullivan, Ewan
Ahn, Eunmo
Lee, Wonki
Cho, Hyejeon
Jee, M. James
van Weeren, Reinout
Lovisari, Lorenzo
Finner, Kyle
Simionescu, Aurora
Forman, William
Shimwell, Timothy
Jones, Christine
Zhu, Zhenlin
Randall, Scott
author_facet Rajpurohit, Kamlesh
Stroe, Andra
O'Sullivan, Ewan
Ahn, Eunmo
Lee, Wonki
Cho, Hyejeon
Jee, M. James
van Weeren, Reinout
Lovisari, Lorenzo
Finner, Kyle
Simionescu, Aurora
Forman, William
Shimwell, Timothy
Jones, Christine
Zhu, Zhenlin
Randall, Scott
contents We report upgraded Giant Metrewave Radio Telescope and Karl J. Jansky Very Large Array radio observations of a low-mass merging galaxy cluster PSZ2 G181.06+48.47. This exceptional galaxy cluster hosts two megaparsec-scale diffuse sources, symmetrically located with respect to the cluster center and separated by about 2.6 Mpc in projection. We detect these low surface brightness sources in our new high-frequency observations (0.3-2 GHz) and classify them as radio relics associated with merger-driven shock fronts. The southwest relic exhibits an inverted morphology and shows evidence of spectral steepening in the post-shock region, potentially tracing a high Mach number shock ($\sim 4$) under the framework of diffusive shock acceleration. The northeast relic is found to be highly polarized with a 22% average polarization fraction at 1.5 GHz and aligned magnetic field vectors. Its spectral and polarization properties, along with the presence of a nearby tailed galaxy, support re-acceleration scenarios. The merger axis defined by the two relics is tilted by $\sim 45$ degree with respect to the plane of the sky, which implies an unprecedented physical separation of $\sim 3.5$ Mpc. We also detect a possible faint radio halo, suggesting weak turbulence in the central cluster region. We conclude that the faint double relics can be best explained by two outward moving shock waves in which particles are (re-)accelerated and that the cluster is in an evolved merger state. PSZ2 G181.06+48.47 presents a unique opportunity to investigate particle acceleration in low mass systems characterized by large relic separations.
format Preprint
id arxiv_https___arxiv_org_abs_2501_08390
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PSZ2 G181.06+48.47 II: radio analysis of a low-mass cluster with exceptionally-distant radio relics
Rajpurohit, Kamlesh
Stroe, Andra
O'Sullivan, Ewan
Ahn, Eunmo
Lee, Wonki
Cho, Hyejeon
Jee, M. James
van Weeren, Reinout
Lovisari, Lorenzo
Finner, Kyle
Simionescu, Aurora
Forman, William
Shimwell, Timothy
Jones, Christine
Zhu, Zhenlin
Randall, Scott
Cosmology and Nongalactic Astrophysics
We report upgraded Giant Metrewave Radio Telescope and Karl J. Jansky Very Large Array radio observations of a low-mass merging galaxy cluster PSZ2 G181.06+48.47. This exceptional galaxy cluster hosts two megaparsec-scale diffuse sources, symmetrically located with respect to the cluster center and separated by about 2.6 Mpc in projection. We detect these low surface brightness sources in our new high-frequency observations (0.3-2 GHz) and classify them as radio relics associated with merger-driven shock fronts. The southwest relic exhibits an inverted morphology and shows evidence of spectral steepening in the post-shock region, potentially tracing a high Mach number shock ($\sim 4$) under the framework of diffusive shock acceleration. The northeast relic is found to be highly polarized with a 22% average polarization fraction at 1.5 GHz and aligned magnetic field vectors. Its spectral and polarization properties, along with the presence of a nearby tailed galaxy, support re-acceleration scenarios. The merger axis defined by the two relics is tilted by $\sim 45$ degree with respect to the plane of the sky, which implies an unprecedented physical separation of $\sim 3.5$ Mpc. We also detect a possible faint radio halo, suggesting weak turbulence in the central cluster region. We conclude that the faint double relics can be best explained by two outward moving shock waves in which particles are (re-)accelerated and that the cluster is in an evolved merger state. PSZ2 G181.06+48.47 presents a unique opportunity to investigate particle acceleration in low mass systems characterized by large relic separations.
title PSZ2 G181.06+48.47 II: radio analysis of a low-mass cluster with exceptionally-distant radio relics
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2501.08390