2013A&A...553A...4N

The Leo Triplet group of galaxies is best known for the impressive bridges of neutral gas that connect its members. One of the bridges forms a large tidal tail extending eastwards from NGC3628 that hosts several HI plumes and carries the material from this galaxy to the intergalactic space. The magnetic fields of the member galaxies NGC3628 and NGC3627 show morphological peculiarities, suggesting that interactions within the group may be caused by stripping of the magnetic field. This process could supply the intergalactic space with magnetised material, a scenario considered as a possible source of intergalactic magnetic fields (as seen eg. in the ``Taffy'' pairs of galaxies). Additionally, the plumes are likely to be the tidal dwarf galaxy candidates. We performed radio continuum mapping observations at 2.64GHz using the 100-m Effelsberg radio telescope. We obtained total power and polarised intensity maps of the Triplet. These maps were analysed together with the archive data, and the magnetic field strength (as well as the magnetic energy density) was estimated. Extended emission was not detected either in the total power or the polarised intensity maps. We obtained upper limits of the magnetic field strength and the energy density of the magnetic field in the Triplet. We detected emission from the easternmost clump and determined the strength of its magnetic field. In addition, we measured integrated fluxes of the member galaxies at 2.64GHz and estimated their total magnetic field strengths. We found that the tidal tail hosts a tidal dwarf galaxy candidate that possesses a detectable magnetic field with a non-zero ordered component. Extended radio continuum emission, if present, is weaker than the reached confusion limit. The total magnetic field strength does not exceed 2.8µG and the ordered component is lower than 1.6µG.