We present observations and models of the kinematics and the distribution of the neutral hydrogen ( H i ) in the isolated dwarf irregular galaxy , Wolf-Lundmark-Melotte ( WLM ) .
We observed WLM with the Green Bank Telescope ( GBT ) and as part of the MeerKAT Early Science Programme , where 16 dishes were available .
The H i disc of WLM extends out to a major axis diameter of 30 \arcmin ( 8.5 kpc ) , and a minor axis diameter of 20 \arcmin ( 5.6 kpc ) as measured by the GBT .
We use the MeerKAT data to model WLM using the TiRiFiC software suite , allowing us to fit different tilted-ring models and select the one that best matches the observation .
Our final best-fitting model is a flat disc with a vertical thickness , a constant inclination and dispersion , and a radially-varying surface brightness with harmonic distortions .
To simulate bar-like motions , we include second-order harmonic distortions in velocity in the tangential and the vertical directions .
We present a model with only circular motions included and a model with non-circular motions .
The latter describes the data better .
Overall , the models reproduce the global distribution and the kinematics of the gas , except for some faint emission at the 2 \sigma level .
We model the mass distribution of WLM with a pseudo-isothermal ( ISO ) and a Navarro-Frenk-White ( NFW ) dark matter halo models .
The NFW and the ISO models fit the derived rotation curves within the formal errors , but with the ISO model giving better reduced chi-square values .
The mass distribution in WLM is dominated by dark matter at all radii .