Origin and Evolution of the $Ω$ Structure in the Head-Tail Radio Galaxy of Abell 3322

Fuente: arXiv
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Auteurs principaux: Kurahara, Kohei, Akahori, Takuya, Ohmura, Takumi, Yoshiura, Shintaro, Ito, Daisuke, Ma, Yik Ki, Nakazawa, Kazuhiro, Omiya, Yuki, Sakai, Kosei, Sakemi, Haruka, Takizawa, Motokazu
Format: Preprint
Publié: 2025
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author Kurahara, Kohei
Akahori, Takuya
Ohmura, Takumi
Yoshiura, Shintaro
Ito, Daisuke
Ma, Yik Ki
Nakazawa, Kazuhiro
Omiya, Yuki
Sakai, Kosei
Sakemi, Haruka
Takizawa, Motokazu
author_facet Kurahara, Kohei
Akahori, Takuya
Ohmura, Takumi
Yoshiura, Shintaro
Ito, Daisuke
Ma, Yik Ki
Nakazawa, Kazuhiro
Omiya, Yuki
Sakai, Kosei
Sakemi, Haruka
Takizawa, Motokazu
contents A head-tail galaxy is thought to be a radio galaxy with bent active galactic nuclei (AGN) jets interacting with the intracluster medium (ICM). Study of head-tail galaxies provides us with fruitful insights into the mechanisms of shock waves and turbulence, as well as magnetic-field amplification and cosmic-ray acceleration. A recent MeerKAT observation revealed that a head-tail galaxy in the galaxy cluster, Abell 3322, exhibits a peculiar ``Omega" structure in its shape. In this paper, we investigated this Omega-tail galaxy using the upgraded Giant Meterwave Radio Telescope (GMRT) and the Australia Telescope Compact Array (ATCA). We found that the southern jet tends to be brighter than the northern jet, with a brightness ratio of about 2. This can be attributed to Doppler boost and the inclination of the jets. Our broadband data suggest that the radio spectrum becomes steeper along the jet propagation direction, and the cosmic-ray aging model with a weak reacceleration of cosmic rays is preferable to explain the index profile. We further found a gradient of the spectral index perpendicular to the jet propagation. We discussed the origin of the gradient and suggested that a shock wave along one side of the jets is present. The resultant ram pressure as well as the backflow made at the early stage of the jet may produce the tail component of this Omega-tail galaxy, while the observed Omega-shape structure is more likely due to a twin vortex seen in the low Reynolds number flow.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03937
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Origin and Evolution of the $Ω$ Structure in the Head-Tail Radio Galaxy of Abell 3322
Kurahara, Kohei
Akahori, Takuya
Ohmura, Takumi
Yoshiura, Shintaro
Ito, Daisuke
Ma, Yik Ki
Nakazawa, Kazuhiro
Omiya, Yuki
Sakai, Kosei
Sakemi, Haruka
Takizawa, Motokazu
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
A head-tail galaxy is thought to be a radio galaxy with bent active galactic nuclei (AGN) jets interacting with the intracluster medium (ICM). Study of head-tail galaxies provides us with fruitful insights into the mechanisms of shock waves and turbulence, as well as magnetic-field amplification and cosmic-ray acceleration. A recent MeerKAT observation revealed that a head-tail galaxy in the galaxy cluster, Abell 3322, exhibits a peculiar ``Omega" structure in its shape. In this paper, we investigated this Omega-tail galaxy using the upgraded Giant Meterwave Radio Telescope (GMRT) and the Australia Telescope Compact Array (ATCA). We found that the southern jet tends to be brighter than the northern jet, with a brightness ratio of about 2. This can be attributed to Doppler boost and the inclination of the jets. Our broadband data suggest that the radio spectrum becomes steeper along the jet propagation direction, and the cosmic-ray aging model with a weak reacceleration of cosmic rays is preferable to explain the index profile. We further found a gradient of the spectral index perpendicular to the jet propagation. We discussed the origin of the gradient and suggested that a shock wave along one side of the jets is present. The resultant ram pressure as well as the backflow made at the early stage of the jet may produce the tail component of this Omega-tail galaxy, while the observed Omega-shape structure is more likely due to a twin vortex seen in the low Reynolds number flow.
title Origin and Evolution of the $Ω$ Structure in the Head-Tail Radio Galaxy of Abell 3322
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2511.03937