| Name: Rupali Hatte |
| Affiliation: B K Birla College of Arts, Science & Commerce |
| Conference ID: ASI2026_996 |
| Title: Moustache or M-shaped radio galaxies: A study through RAD@home citizen science |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Rupali Hatte(B K Birla College of Arts, Science & Commerce, RAD@home India), Dr Ananda Hota(UM-DAE CEBS & CETACS, University of Mumbai, and RAD@home India), Avinash Kumar(RAD@home India), Mitali Damle(RAD@home India), Ninisha Manaswini(RAD@home India), Utpal Nundy(RAD@home India), Prasun Machado(RAD@home India), Aditya Sahasranshu(RAD@home India), Arundhati Purohit(RAD@home India) |
| Abstract: We present an analysis of three rare M-shaped (or “moustache”) radio galaxies discovered through RAD@home citizen-science research. Unlike FR I, FR II, WAT, HT, DDRG, and S/Z/X-shaped radio galaxies, M-shaped radio galaxies remain largely unexplored. In all the cases presented here, the radio jets are launched from galaxies that are in the process of merging with companions. These sources were identified through a network of trained citizen scientists, or e-/i-astronomers. NVSS–DSS–TGSS radio–optical–radio RGB contour images of the large-scale emission show a morphology broadly resembling wide-angle-tailed sources. However, higher-resolution observations with FIRST, VLASS, and RACS reveal finer jet structures near the host galaxies, including a central surface-brightness depression that produces the characteristic M-shape. We interpret this central depression as a consequence of the motion of the host galaxy around the centre of mass of the interacting system. Furthermore, in one case the M-shaped structure is not orthogonal to the large-scale orbital plane of the merging galaxies, which is traced by an extended stellar disk. Since buoyancy effects are unlikely to dominate in this configuration, the observed asymmetries in the small-scale jets are interpreted as interactions with a rotating interstellar medium (ISM), where the jet propagates with the ISM rotation on one side and against it on the other. As demonstrated by the recently discovered case of jet–companion-galaxy interaction (RAD-12) identified by RAD@home, such distortions can be dramatic. How AGN jets or winds couple to the ISM remains poorly constrained in models of galaxy evolution driven by mergers and AGN feedback. Jet distortions observed during galaxy mergers therefore provide compelling evidence that such systems constitute important laboratories for understanding AGN feedback, particularly through coordinated multi-wavelength follow-up observations.
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