| Name: DEVIKA P C |
| Affiliation: MANIPAL CENTRE FOR NATURAL SCIENCES |
| Conference ID: ASI2026_276 |
| Title: Evidence of diffuse radio emission from a galaxy group falling into a node of the cosmic web |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Devika P C(Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Manipal -576 104, India), Surajit Paul(Manipal Centre for Natural Sciences, Manipal Academy of Higher Education. Manipal -576 104, India) |
| Abstract: Diffuse radio emission provides a powerful probe of non-thermal processes occurring in galaxy clusters and groups, which will contribute to the understanding of hierarchical structure formation along the cosmic web. While such emission is well studied in massive merging clusters, its presence and origin in low-mass systems are poorly understood.
According to our hypothesis, low-mass clusters or galaxy groups infalling toward a central massive cluster are expected to host large-scale diffuse radio emission generated by dynamical activity arising from their interaction. So here we are, presenting low-frequency radio analysis of the dynamically complex Abell 2069 system, focusing on its low-mass companion (A2069B), which is interacting with the massive cluster Abell 2069A. Using archival uGMRT Band-3 (300–500 MHz) data combined with 144 MHz LOFAR LoTSS-DR2 images, we investigate the nature and extent of diffuse radio emission associated with both components. We detect large-scale diffuse synchrotron emission associated with A2069B, extending over ∼370 kpc—significantly larger than typical radio mini-halos observed in low-mass systems. The integrated spectral index measured between 144 and 400 MHz is α ≈ −1.2, confirming the diffuse emission is of intra-cluster medium origin. The emission spatially coincides with the galaxy concentration and X-ray emission, indicating a strong connection between the observed radio emission and ongoing dynamical activity.
Our results suggest that turbulence generated by the infall of a galaxy group/low-mass cluster along cosmic filaments can efficiently re-accelerate relativistic particles well before core passage. This study highlights infalling groups as important sites of particle acceleration and demonstrates the critical role of lo
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