NGC 1487 MeerKAT image

Dwarf galaxies are important laboratories for studying cosmic magnetism because they can maintain strong magnetic fields via the action of turbulent dynamo despite their low mass and weak gravitational potential. The Magnetic-field Evolution in Dwarf galaxies from Ultra-deep SKA Analysis (MEDUSA) survey is the first SKA-pathfinder programme designed to obtain deep continuum, polarisation, and HI data for dwarf galaxies, enabling a comprehensive study of their radio spectra, magnetic fields, and gas kinematics across a representative population By analysing the radio continuum spectra and polarisation of the dwarf-dwarf galaxy merger NGC 1487 from the MEDUSA sample, our aim was to determine its magnetic field strength and to characterise the large-scale and turbulent components of its magnetic field.

We utilised highly sensitive multi-band radio continuum data from MeerKAT L-band (1.28GHz) and Australia Telescope Compact Array (ATCA) L/S (2.1GHz), C (5.5GHz), and X-bands (9GHz). We analysed the magnetic field configuration using polarisation and rotation measure (RM) synthesis. The integrated spectral energy distribution has a non-thermal spectral index of {alpha}nth=-0.678+/-0.085, indicating a significant synchrotron contribution, consistent with a CR electron injection index of gamma=2.36 (N(E){prop.to}E^-gamma^) typical of supernova remnants.