MIGHTEE–HI: H i catalogue of 293 sources for the COSMOS field and comparative study of 3-dimensional source finding methods

We present a catalogue of H i sources extracted from the MIGHTEE survey data cubes covering the COSMOS field. The catalogue contains 293 sources in the redshift range of . In addition to H i masses and velocity widths, the catalogue includes optical through near-infrared photometry and inferred stellar masses and star-formation rates. The quantity of sources in the H i catalogue acquired through untargeted source finding is greatly influenced by the source finding methods used. This study therefore also provides a well-characterized expected completeness of the detected sample of galaxies based on their properties, informing of any detection biases, inferred through a comparative study of different source finding algorithms. We have tested the performance of widely-used source finders: pybdsf, profound, and sofia, along with new source finder leshi, focusing exclusively on H i source detection rather than source characterization in the first instance. The source finders were tested by injecting a sample of simulated galaxies divided into narrow bins of mass, inclination and distance into a MeerKAT data cube. The results inform the source finding strategies for the MeerKAT International GigaHertz Tiered Extragalactic Exploration (MIGHTEE) survey, as well as upcoming SKAO surveys.