The MWA Interestingly Deep AStrophysical (MIDAS) Survey: Survey Description and First Data Release

We present the deepest MWA survey to date, targeting the GAMA9 and GAMA23 survey fields at 215.68 MHz. With a bandwidth of 30.72 MHz, the two images cover about 1250 deg squared for the GAMA9 field and about 850 deg squared for the GAMA23 field, with an angular resolution of about 60''. The GAMA9 image was formed from 1 282 2-min snapshot observations (42.7 hours) and the GAMA23 image from 1 701 observations (56.7 hours) achieving depths of 0.923 plus or minus 0.003 and 0.331 plus or minus 0.001 mJy/beam at the field centres respectively. We processed the data with an updated version of the GLEAM-X pipeline tuned for deep surveys and make this MWA Deep Imaging Pipeline code public. Updates to the pipeline include automation of the observation downloading, calibration, and imaging along with optimisation of the CLEANing methods and parameters. Above 5σ, we catalogue 53 419 and 80 407 radio components in the GAMA9 and GAMA23 fields respectively. We find that the completeness corrected source counts for both fields are in good agreement down to 25 - 50 mJy with those from LOFAR and earlier MWA surveys. We demonstrate the utility of this survey by highlighting a few sources of particular interest and describing future science possible with this survey.