The MeerKLASS UHF On-the-Fly Continuum Survey -- Data Release I

TL;DR

This paper presents the first public data release from the MeerKLASS UHF survey, demonstrating a novel on-the-fly mapping technique with high-quality continuum images and a large radio source catalog, validating the approach for future large-area surveys.

Contribution

It introduces an innovative on-the-fly mapping method for radio surveys and provides the first data release with validated source catalogues, enabling efficient large-area sky observations.

Findings

Produced high-fidelity continuum images covering 800 deg$^2$

Detected nearly 95,000 radio sources with accurate astrometry

Validated data quality through cross-matching and source counts

Abstract

We present the first public data release (DR1) from the interferometric component of the MeerKAT Large Area Synoptic Survey (MeerKLASS) UHF survey, a legacy program demonstrating a novel on-the-fly (OTF) mapping technique. This release is based on 12 hours of early science observations covering approximately 800 deg$^2$ of the southern sky. We describe the data processing pipeline developed to calibrate and image these fast-scanning observations, producing high-fidelity continuum images at a central frequency of 816 MHz. The resulting mosaic reaches an RMS sensitivity of $\sim$35 $\mu$Jy beam$^{-1}$ in its deepest regions, with a typical angular resolution of $\sim32'' \times 17''$. In these images, we identify $95483$ radio sources. We validate the catalogue through cross-matching with external surveys, confirming sub-arcsecond astrometric accuracy and a robust flux density scale. We compute the differential source counts, finding excellent agreement with existing measurements and validating our end-to-end processing. The success of this pilot study serves as a crucial proof of concept for the OTF observing strategy, and the public release of the images and source catalogue provides a valuable resource for a wide range of astrophysical studies. This work paves the way for the full MeerKLASS OTF survey and future large-area survey projects with the SKA.