The SARAO MeerKAT 1.3 GHz Galactic Plane Survey compact source catalogue

We present a catalogue of compact sources detected in the SARAO MeerKAT 1.3 GHz Galactic Plane Survey (SMGPS). We extract 510 599 compact sources, with areas less than five 8” beams, from the survey maps covering the regions 252° < l < 358° and 2° < l < 61° at |b| < 1.5°, which have an angular resolution of 8” and a sensitivity of ∼ 10-30 μ Jy beam−1. In this paper, we describe the source identification and characterisation methods, present the quality assurance of the catalogue, explore the nature of the catalogue sources, and present initial science highlights. We limit our catalogue to sources with a signal-to-noise ratio ≥5, as the catalogue is ∼90percnt complete, and has a false positive rate of less than 1percnt at this threshold. The bulk of the catalogue sources are previously unknown to the literature, with the majority of unknown sources at sub-mJy levels. Initial science highlights from the catalogue include the detection of 213 radio quiet WISE H ii region candidates, previously undetected in radio continuum studies. We show images that compare the SMGPS compact sources to CORNISH ultracompact H ii regions, thus highlighting the sensitivity and unprecedented uv-coverage of the SMGPS, and the potential synergy of the SMGPS with other surveys.