Bruno, L.L.BrunoBOTTEON, AndreaAndreaBOTTEONShimwell, T.T.ShimwellCuciti, V.V.CucitiDE GASPERIN, FrancescoFrancescoDE GASPERINBRUNETTI, GianfrancoGianfrancoBRUNETTIDALLACASA, DanieleDanieleDALLACASAGASTALDELLO, FabioFabioGASTALDELLOROSSETTI, MariachiaraMariachiaraROSSETTIvan Weeren, R. J.R. J.van WeerenVENTURI, TizianaTizianaVENTURIRusso, S. A.S. A.RussoTAFFONI, GiulianoGiulianoTAFFONICASSANO, RossellaRossellaCASSANOBiava, N.N.BiavaLusetti, G.G.LusettiBONAFEDE, AnnalisaAnnalisaBONAFEDEGHIZZARDI, SIMONASIMONAGHIZZARDIDE GRANDI, SabrinaSabrinaDE GRANDI2025-02-192025-02-1920230004-6361http://hdl.handle.net/20.500.12386/36056Context. Turbulence introduced into the intracluster medium (ICM) through cluster-merger events transfers energy to non-thermal components, and can trigger the formation of diffuse synchrotron radio sources. Typical diffuse sources in the form of giant radio halos and mini-halos are found in merging and relaxed cool-core galaxy clusters, respectively. On the other hand, recent observations reveal an increasing complexity to the non-thermal phenomenology. <BR /> Aims: Abell 2142 (A2142) is a mildly disturbed cluster that exhibits uncommon thermal and non-thermal properties. It is known to host a hybrid halo consisting of two components (H1 and H2), namely a mini-halo-like and an enigmatic elongated radio halo-like structure. We aim to investigate the properties, origin, and connections of each component. <BR /> Methods: We present deep LOFAR observations of A2142 in the frequency ranges 30-78 MHz and 120 − 168 MHz. With complementary multi-frequency radio and X-ray data, we analysed the radio spectral properties of the halo and assessed the connection between the non-thermal and thermal components of the ICM. <BR /> Results: We detect a third radio component (H3), which extends over the cluster volume on scales of ∼2 Mpc, embeds H1 and H2, and has a morphology that roughly follows the thermal ICM distribution. The radio spectral index is moderately steep in H1 (α = 1.09 ± 0.02) and H2 (α = 1.15 ± 0.02), but is steeper (α = 1.57 ± 0.20) in H3. Our analysis of the thermal and non-thermal properties allowed us to discuss possible formation scenarios for each radio component. Turbulence from sloshing motions of low-entropy gas on different scales may be responsible for the origin of H1 and H2. We classified H3 as a giant ultrasteep spectrum radio halo, and find that it may trace the residual activity from an old energetic merger and/or inefficient turbulent reacceleration induced by ongoing minor mergers.STAMPAenArticle10.1051/0004-6361/2023472452-s2.0-85175054150https://www.aanda.org/articles/aa/full_html/2023/10/aa47245-23/aa47245-23.htmlhttp://arxiv.org/abs/2308.07603v12023A&A...678A.133BFIS/05 - ASTRONOMIA E ASTROFISICA