Evidence for in-situ acceleration of relativistic particles in the wings of X-shaped radio galaxies

Fuente: arXiv
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Main Authors: Patra, Dusmanta, Gopal-Krishna, Joshi, Ravi
Format: Preprint
Published: 2025
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author Patra, Dusmanta
Gopal-Krishna
Joshi, Ravi
author_facet Patra, Dusmanta
Gopal-Krishna
Joshi, Ravi
contents We report evidence for in-situ acceleration/re-acceleration of relativistic particles in 11 radio wings out of a total of 68 wings sufficiently well-resolved for spectral mapping, which belong to our sample of 40 X-shaped radio galaxies (XRGs). This representative XRG sample includes 15 XRGs newly reported here, which we selected from the LOTSS-DR2 survey, following well-defined criteria. The evidence for in-situ particle acceleration comes from the observed cessation of steepening, or even flattening (i.e., gradient reversal) of the spectral index profile along the lobe into the associated wing, as determined here by combining the LoTSS-DR2 (144 MHz) and FIRST (1.4 GHz) maps. Interestingly, the afore-mentioned trends in spectral gradient, indicative of in-situ particle acceleration, are mostly found to set in near the region where the lobe plasma stream bends to connect to the wing. Such a spatial coincidence with bending of radio lobe/tail has been noticed in recent years for just a couple of radio galaxies. The large increase in such examples, as reported here, is expected to give a fillip to observational, theoretical and numerical simulation follow-up investigations of this important clue about the occurrence of in-situ particle acceleration in lobes of radio galaxies.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08676
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evidence for in-situ acceleration of relativistic particles in the wings of X-shaped radio galaxies
Patra, Dusmanta
Gopal-Krishna
Joshi, Ravi
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
We report evidence for in-situ acceleration/re-acceleration of relativistic particles in 11 radio wings out of a total of 68 wings sufficiently well-resolved for spectral mapping, which belong to our sample of 40 X-shaped radio galaxies (XRGs). This representative XRG sample includes 15 XRGs newly reported here, which we selected from the LOTSS-DR2 survey, following well-defined criteria. The evidence for in-situ particle acceleration comes from the observed cessation of steepening, or even flattening (i.e., gradient reversal) of the spectral index profile along the lobe into the associated wing, as determined here by combining the LoTSS-DR2 (144 MHz) and FIRST (1.4 GHz) maps. Interestingly, the afore-mentioned trends in spectral gradient, indicative of in-situ particle acceleration, are mostly found to set in near the region where the lobe plasma stream bends to connect to the wing. Such a spatial coincidence with bending of radio lobe/tail has been noticed in recent years for just a couple of radio galaxies. The large increase in such examples, as reported here, is expected to give a fillip to observational, theoretical and numerical simulation follow-up investigations of this important clue about the occurrence of in-situ particle acceleration in lobes of radio galaxies.
title Evidence for in-situ acceleration of relativistic particles in the wings of X-shaped radio galaxies
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2511.08676